Improved iOS 7 Animation: Iteration #1

This is an improved animation for the animation types `slide-left-right-ios7` and `nav-title-slide-ios7`. This one more closely matches the native iOS 7 navigation transition style. Some things I changed:

1. The animation duration has increased
2. The animation now uses a custom `cubic-bezier` easing curve instead of `ease-in-out` which was not accurate
3. The `.title` on the entering view now slides in from all the way on the right instead of 15% over.
4. The reverse animation for this type is fixed. It was not implemented correctly it seems.

This is the smallest set of changes. I am working on more intense changes for fixing the way `nav-buttons` animate (they should fade out), as well as darkening the fading out content area and auto-creating the back button text from the last title (as an optional directive) and fixing that animation. Also, I am working on a better animation for those using Android.