Merge pull request #12 from wuzhiming/plugin_fb_3rd

Plugin fb 3rd
delete useless code in jsb_pluginx.js
add code for handling login failed
add comments
Merge pull request #13 from wuzhiming/plugin_fb_3rd

fix some bug for plugin
Merge pull request #14 from joshuastray/plugin_fb_3rd

fix pluign-x bugs
isLogedIn -> isLoggedIn
Merge pull request #15 from joshuastray/plugin_fb_3rd

isLogedIn -> isLoggedIn
add facebook async methods
fix login failed bug
fix bugs
Merge pull request #16 from joshuastray/plugin_fb_3rd

add facebook async methods
delete unuse lines
add plugin.FacebookAgent.CodeSucceed constant
add getSDKVersion method
Merge pull request #17 from joshuastray/plugin_fb

add plugin.FacebookAgent.CodeSucceed constant
Merge branch 'plugin_fb' of https://github.com/pandamicro/plugin-x into plugin_fb_3rd
modify the isLoggedIn function.