fix(swipeEnd): prevent buttons inside slider to trigger swipeEnd
Buttons inside slider (like prev/next buttons) can trigger the swipeEnd event on click (because of touchend/mouseup from $swipe).
This cause the slider to stand on some browsers, even if the index is updated.
Closes #115
Merge pull request #116 from leeroybrun/master

fix(swipeEnd): prevent buttons inside slider to trigger swipeEnd