fixed #1636: Refactored CCEditBox for iOS, moved the implementation of EditBoxImplIOS.h/.cpp to CCEditBoxImplIOS.h/.cpp.
fixed #1636: Deleted CC_ENABLE_CHIPMUNK_INTEGRATION and CC_ENABLE_BOX2D_INTEGRATION in ccConfig.h since they are moved to extension, it doesn't depend on engine any more.
Added platform macro for CCEditBoxImpl* files.
Merge pull request #1819 from dumganhar/gles20

fixed #1636: Refactored CCEditBox for iOS, moved the implementation of EditBoxImplIOS.h/.cpp to CCEditBoxImplIOS.h/.cpp.
Deleted CC_ENABLE_CHIPMUNK_INTEGRATION and CC_ENABLE_BOX2D_INTEGRATION in ccConfig.h since they are moved to extension, it doesn't depend on engine any more.