Remove deprecated webkitImageSmoothingEnabled

[jackfranklin]

I kept getting that warning in the console, so I figured I'd remove the offending line.

Thank you for all your work on an awesome module :)

[Wildhoney]

@jackfranklin Thanks!

I found it annoying as well, but it seems we need it for Safari.

Maybe we could do a small Chrome detection to set webkitImageSmoothingEnabled using navigator.userAgent.toLowerCase().indexOf('chrome'), that way:

• If it is Chrome, we can remove the webkit prefixed property, fixing the irritating message;
• If it isn't Chrome, it'll always add the prefixed property;
• If it's Chrome but UA is different, we'll simply get the current behaviour;