Merge pull request #1 from wuzhiming/plugin_fb

feature #5592 add Facebook to pluginX
Feature #5592: Add PluginFacebook lib
Merge branch 'plugin_fb' of https://github.com/pandamicro/cocos2d-js into plugin_fb

Conflicts:
	build/cocos2d_jsb_samples.xcodeproj/project.pbxproj
Feature #5592: Fix sdk import issue
feature #5592 add Facebook to pluginX   finish Facebook user