Buildsystem: Overhaul of the CMake buildsystem:

- utilize CMake for completely generating revision.h (kills off genrev and revision.h targets):
  - pull and set correct revision-ID/hash from Mercurial (hg) when using regular repository sourcetree
  - pull and set correct revision-ID/hash from archived releases (when pulled from googlecode)
  - set and use _BUILD_DIRECTIVE definition (earlier part of revision.h) as compiletime definition
- delete genrev and related buildsystems
  (now deprecated)
- Move some files around to adhere to buildsystem structure
Thanks to Shauren for figuring out the definition-behaviour for MSVC while he was in the shower

--HG--
branch : trunk
rename : cmake_uninstall.cmake.in => cmake/platform/unix/cmake_uninstall.in.cmake

cmake/showoptions.cmake

@@ -1,7 +1,7 @@
 # output generic information about the core and buildtype chosen
 
 message("")
-message("* TrinityCore revision   : ${HG_REVISION}")
+message("* TrinityCore revision   : ${hg_rev_id_str} (${hg_rev_hash_str})")
 if( UNIX )
   message("* Build binaries in      : ${CMAKE_BUILD_TYPE} mode")
 endif()