Add selection weights to BG and Arenas. Will determine the selected BG/Arena chosen using random BG/Arenas from the enabled list.

Closes issue 2843

--HG--
branch : trunk

sql/updates/9135_world_battleground_template.sql

@@ -0,0 +1 @@
+ALTER TABLE `battleground_template` ADD `Weight` tinyint(2) UNSIGNED NOT NULL DEFAULT 1 AFTER `HordeStartO`;