fixed shader compiler after cocos refactor
added missing pch files for WP8
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into wp8-v3-fix
updated precompiled shaders for wp8
updated pch file for wp8
updated link() for wp8
Merge pull request #6857 from Dhilan007/v3_labelfix

issue #5277:Label:It could be possible that for using outline and invoking 'Director::setContentScaleFactor' cause label show nothing.
Merge pull request #6854 from MSOpenTech/wp8-v3-fix

Wp8 v3 fix for precompiled shaders and precompiled headers