Fix "Go back to Slide 0 = Broken".

Fixed as described in
https://github.com/woothemes/FlexSlider/issues/201#issuecomment-9594333

We experience this issue when sliding to the last slide of a flexslider
instance programmatically as well as for the slide to the first one as
described in the issue above.

Using flexslider with animationLoop:false.

Mainly forked because we're using Twitter Bower.