fixed #1652: Rename cc.TEXTURE_2D_PIXEL_FORMAT_xxx to cc.TEXTURE_PIXELFORMAT_xxx
issue #1652: remove useless code
issue #1652: update tests commit ID
Merge pull request #729 from linshun/iss1652_texture2d

Rename cc.TEXTURE_2D_PIXEL_FORMAT_xxx to cc.TEXTURE_PIXELFORMAT_xxx