fix($animate): use a scheduled timeout in favor of a fallback property to close transitions

With ngAnimate, CSS transitions, that are not properlty triggered, are forceably closed off
by appling a fallback property. The fallback property approach works, however, its styling
itself may effect CSS inheritance or cause the element to render improperly. Therefore, its
best to stick to using a scheduled timeout to run sometime after the highest animation time
has passed.

Closes #5255
Closes #5241
Closes #5405
style(animateSpec): ensure spacing between specs and describes is consistent
Merge branch 'master' of https://github.com/angular/angular.js