fix Build unchecked md5 will report an error for issues/7845 (cocos#2955

)

Merge 1.9

# Conflicts:
#	cocos2d/core/videoplayer/CCSGVideoPlayer.js

Merge branch 'v1.9'

Merge branch 'v1.9-release'

Fix issues (cocos#2608)

* Add missed vec3 APIs

* Fix Node property setter issue

* Fix scene dirty sync issue

* Fix setWorldRot not setting dirty issue

update version to 1.6.0