refactor(interimElement, animate): improve logic with promise chains …

…and timeouts

waitTransitionEnd() rejects only if timeout occurs
interimElement
- use of try/catch with onShow and onRemove callbacks
- improved capture of exceptions and rejections
- .show() promise will resolve only if both the show and hide actions resolve
- .show() has improved logic for removing existing interimElement before showing new one
- $log used to notify developer of waitTransitionEnd timeouts
- corrected usages of promise chains and exposure of unique `interimElement.deferred.promise`
- added logic tests for .show() and .hide() with rejections and exceptions.