issue #2790: Updates CCValue, supports using ‘const char*’ to construct a Value.
issue #2790: NULL —> nullptr in CCParticleSystem.cpp.
issue #2790: Assert fix for Vector<T>::insertObject.
issue #2790: Uses ValueDict instead of Dictionary* for ParticleSystem.
issue #2790: Uses cocos2d::Map and ValueDict for SpriteFrameCache.
issue #2790: const char* —> const std::string&   for CCNS.h/.cpp.
issue #2790: Uses const reference instead of value for std::for_each ’s argument.
issue #2790: Don’t make an assert if converting Value failed.