[2.1.5] Fixing black screen on android. Refer to https://github.com/cocos2d/cocos2d-x/pull/3117 .
[2.1.5] Fixing a typo: EVNET_ --> EVENT_
[2.1.5] Adding listener for CCDrawNode when application resume from background. Observer was set only when CC_ENABLE_CACHE_TEXTURE_DATA was enabled in CCParticleSystemQual.cpp.
[2.1.5] Resetting VAO in ccGLInvalidateStateCache.
[2.1.5] Observer is added only when CC_ENABLE_CACHE_TEXTURE_DATA is enabled in CCTextureAtlas.cpp.
[2.1.5] Fixing an error in CCShaderCache.cpp.
[2.1.5] Re-order of recovering GL status in jni/xxx/main.cpp.
[2.1.5] Fixing the issue here (http://www.cocos2d-x.org/issues/2401). CCLabelBMFont crashes in glDrawElements of CCTextureAtlas::drawNumberOfQuads sometimes
[2.1.5] Fixing an issue which is resolved in cocos2d-x 3.0 (https://github.com/cocos2d/cocos2d-x/pull/3369) .
[2.1.5] Object --> CCObject for CCDrawNode::listenBackToForeground.
[2.1.5] Fixing a compilation error after enabling CC_ENABLE_CACHE_TEXTURE_DATA .
[2.1.5] Fixing a bug that resolved at cocos2d-x 3.0. (http://www.cocos2d-x.org/issues/2388).
[2.1.5] Fixing a bug resolved in cocos2d-x 3.0. (http://www.cocos2d-x.org/issues/2398)
[MAC] Adding Support for initializing Image with raw data.
[2.1.5] Adding test for issue http://www.cocos2d-x.org/issues/2401 .
[2.1.5] setDefaultValue after load config file.
[2.1.5] Updating travis-ci script (before-install.sh).
[2.1.5] Fixing compilation errors when using android-ndk-r9.
[2.1.5] Travis-ci is using android-ndk-r9 now.
[2.1.5] Fixing a bug that resolved in 3.0 (http://www.cocos2d-x.org/issues/2612).
[2.1.5] [NaCL] Add missing include of <sys/mount.h>

This was previously included by nacl_io.h but
upstrean changes in NaCl removed this.