[ci skip] Update CHANGELOG

CHANGELOG

@@ -1,4 +1,4 @@
-cocos2d-x-3.4beta0  ??
+cocos2d-x-3.4beta0  Dec.31 2014
     [NEW]           3D: support frustum culling
     [NEW]           Action: MoveTo and MoveBy support Vec3
     [NEW]           Allocator: add custom allocator support, global, default, fixed block, object pool
@@ -16,13 +16,13 @@ cocos2d-x-3.4beta0  ??
     [FIX]           Label: content size of Label is incorrect if the string is set to empty string
     [FIX]           GLProgramState: fix assert error caused by outdated uniform and attribute cache
 
-cocos2d-x-3.3 Dec.12
+cocos2d-x-3.3 Dec.12 2014
     [FIX]           Billboard: allow billboard rotate along z axis
     [FIX]           Bundle3D: create aabb for mesh whose aabb does not exist (user custom mesh)
     [FIX]           EditBox: text position and move animation error on iPhone6 Plus
     [FIX]           FileUtils: createDirectory(): doesn't invoke closedir() after opendir on platforms other than WP8/WinRT/Windows
 
-cocos2d-x-3.3-rc2  Dec.5
+cocos2d-x-3.3-rc2  Dec.5 2014
     [FIX]           C++: use 100% of one core on Windows
     [FIX]           Label: when a label is added to a invisible parent node, app will crash if switching from background
     [FIX]           Label: label will not be shown when using system font on Mac