Vignette Update

@drsnyder 
New supported modes in PHP client: scale-to-width, window-crop, window-crop-fixed. Also removing `Wikia
\Vignette\FileInterface` and replaced with `Wikia\Vignette\UrlConfig`, which doesn't relate to Wikia File objects at all, so integration with Huddler should be smoother. Changed uses of UrlGenerator to work with `Vignette::fromFile`
Good idea