fix(SlideDrag) clears drag when list is scrolled or new drag starts

This also fixes the broken $ionicListDelegate.clearOptionButtons() method.

Makes lists feel more natural inline with iOS functionality and fixes issues
with using ion-option-buttons with collection repeat
Merge pull request #2558 from mallzee/slide-drag-clear

fix(SlideDrag): clears drag when list is scrolled or new drag starts
fix(tabs): fix goToHistoryRoot
chore($ionicViewService): deprecate
refactor(uiRouter): updates for Angular v1.3
docs(ionicConfig): added navBar config
docs(ionicConfig): update navBar config
refactor(viewEvents): create loaded, enter, leave

Add to the possible events emitted from the view’s scope,
$ionicView.loaded, $ionicView.enter, $ionicView.leave, in addition to
the existing events.
docs(view): view lifecycle and events