Core/Spells: spell effect handling improvements

* Call spell effect handlers in 4 modes:
   - SPELL_EFFECT_HANDLE_LAUNCH - called when spell is launched (cast just finished)
   - SPELL_EFFECT_HANDLE_LAUNCH_TARGET - called when spell is launched for each target in spell target map
   - SPELL_EFFECT_HANDLE_HIT - called when spell hits its destination
   - SPELL_EFFECT_HANDLE_HIT_TARGET - called when spell hits it's target from spell target map
*Correctly implement SPELL_EFFECT_TRIGGER_SPELL, SPELL_EFFECT_TRIGGER_SPELL_WITH_VALUE, SPELL_EFFECT_TRIGGER_MISSILE_SPELL_WITH_VALUE, SPELL_EFFECT_TRIGGER_MISSILE_SPELL
*Remove spell system hacks which became obsolete with this commit
Core/SpellScripts:
add OnEffectLaunch, OnEffectLaunchTarget, OnEffectHit, OnEffectHitTarget hooks for new effect handle modes and remove OnEffect hook.
A generic rule of thumb how to update your scripts (will work for nearly all cases) for spell system noobs:
if your spell script used GetHitXXXX function, you need to use OnEffectHitTarget, otherwise use
OnEffectHit

src/server/scripts/Spells/spell_generic.cpp

@@ -205,7 +205,7 @@ class spell_gen_cannibalize : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_cannibalize_SpellScript::HandleDummy, EFFECT_0, SPELL_EFFECT_DUMMY);
+                OnEffectHit += SpellEffectFn(spell_gen_cannibalize_SpellScript::HandleDummy, EFFECT_0, SPELL_EFFECT_DUMMY);
                 OnCheckCast += SpellCheckCastFn(spell_gen_cannibalize_SpellScript::CheckIfCorpseNear);
             }
         };
@@ -320,7 +320,7 @@ class spell_gen_pet_summoned : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_pet_summoned_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHit += SpellEffectFn(spell_gen_pet_summoned_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -349,7 +349,7 @@ class spell_gen_remove_flight_auras : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_remove_flight_auras_SpellScript::HandleScript, EFFECT_1, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_remove_flight_auras_SpellScript::HandleScript, EFFECT_1, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -491,7 +491,7 @@ class spell_gen_trick : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_trick_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_trick_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -540,7 +540,7 @@ class spell_gen_trick_or_treat : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_trick_or_treat_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_trick_or_treat_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -620,7 +620,7 @@ class spell_pvp_trinket_wotf_shared_cd : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_pvp_trinket_wotf_shared_cd_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_DUMMY);
+                OnEffectHit += SpellEffectFn(spell_pvp_trinket_wotf_shared_cd_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_DUMMY);
             }
         };
 
@@ -709,7 +709,7 @@ class spell_gen_divine_storm_cd_reset : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_divine_storm_cd_reset_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_DUMMY);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_divine_storm_cd_reset_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_DUMMY);
             }
         };
 
@@ -741,7 +741,7 @@ class spell_gen_gunship_portal : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_gunship_portal_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_gunship_portal_SpellScript::HandleScript, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -882,8 +882,8 @@ class spell_generic_clone : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_generic_clone_SpellScript::HandleScriptEffect, EFFECT_1, SPELL_EFFECT_SCRIPT_EFFECT);
-                OnEffect += SpellEffectFn(spell_generic_clone_SpellScript::HandleScriptEffect, EFFECT_2, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_generic_clone_SpellScript::HandleScriptEffect, EFFECT_1, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_generic_clone_SpellScript::HandleScriptEffect, EFFECT_2, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -990,7 +990,7 @@ class spell_generic_clone_weapon : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_generic_clone_weapon_SpellScript::HandleScriptEffect, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_generic_clone_weapon_SpellScript::HandleScriptEffect, EFFECT_0, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -1038,7 +1038,7 @@ class spell_gen_seaforium_blast : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_seaforium_blast_SpellScript::AchievementCredit, EFFECT_1, SPELL_EFFECT_GAMEOBJECT_DAMAGE);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_seaforium_blast_SpellScript::AchievementCredit, EFFECT_1, SPELL_EFFECT_GAMEOBJECT_DAMAGE);
             }
         };
 
@@ -1170,7 +1170,7 @@ class spell_gen_magic_rooster : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_magic_rooster_SpellScript::HandleScript, EFFECT_2, SPELL_EFFECT_SCRIPT_EFFECT);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_magic_rooster_SpellScript::HandleScript, EFFECT_2, SPELL_EFFECT_SCRIPT_EFFECT);
             }
         };
 
@@ -1250,7 +1250,7 @@ class spell_gen_launch : public SpellScriptLoader
 
             void Register()
             {
-                OnEffect += SpellEffectFn(spell_gen_launch_SpellScript::HandleScript, EFFECT_1, SPELL_EFFECT_FORCE_CAST);
+                OnEffectHitTarget += SpellEffectFn(spell_gen_launch_SpellScript::HandleScript, EFFECT_1, SPELL_EFFECT_FORCE_CAST);
                 AfterHit += SpellHitFn(spell_gen_launch_SpellScript::Launch);
             }
         };
@@ -1349,7 +1349,7 @@ public:
 
         void Register()
         {
-        OnEffect += SpellEffectFn(spell_gen_oracle_wolvar_reputation_SpellScript::HandleDummy, EFFECT_0, SPELL_EFFECT_DUMMY);
+            OnEffectHit += SpellEffectFn(spell_gen_oracle_wolvar_reputation_SpellScript::HandleDummy, EFFECT_0, SPELL_EFFECT_DUMMY);
         }
     };