issue #4660: Adds ConvertUTF lib and adds license (LLVM and unicode license).
issue #4660: Refactors utf8 api, make it safer and easier to use.
issue #4660: StringUtils is a namespace now
issue #4660: Updates Xcode project
issue #4660: Updates android.mk
issue #4660: Uses new utf api for Label.
issue #4660: Adds ConvertUTFWrapper.cpp, using llvm::ConvertUTF8toWide and llvm:: convertUTF16ToUTF8String
issue #4660: Oops, utf16 is 2 bytes.
issue #4660: Updates Android.mk
Updates CMakeLists.txt
Updates 2d/CMakeLists.txt
issue #4660: Linux build ok
issue #4660: Updates win32 project
issue #4660: A warning fix in CCFontAtlas.cpp
issue #4660: Fix windows include path doesn't contain `external/ConvertUTF`
issue #4660: CCTweenFunction.h/.cpp must be in 'action' filter
issue #4660:remove unnecessary API.
issue #4660: Removes unused function in ccUTF8.cpp
issue #4660: Updates comments and doc for deprecated ccutf8 api
issue #4660: Adds utf8/16 conversion unit test