fixed FontAtlasCache::getFontAtlasCharMap may returns the same instance when using different arguments.
replace sprintf with snprintf
Update CCFontAtlasCache.cpp
Merge pull request #7559 from minggo/fix-xcode-project

fix the bug that cocos2d_libs.xcodeproj can not be opened in cocos2d_test.xcodeproj
Merge pull request #7556 from Dhilan007/v3

fixed FontAtlasCache::getFontAtlasCharMap may returns the same instance when using different arguments.