Tweaks to compound animations

[memmons]

Some of the compound animations such as the backInFrom and backInTo could use a bit of tweaking. For example, using backInFrom with any duration > 0.5 starts looking strange because the 2nd part of the animation where the view backs up a bit is using the same velocity as the 1st part. IMO, duration should only affect the time it takes to get to the end of the 1st part of the animation, before the view backs up a bit.

Likewise, backInTo's duration should only affect the 2nd part of the animation, after the view backs up.

[neror]

I agree. The animation stuff is starting to show its age, and it could use some updating/refactoring. Feel free to make any tweaks you want and send me a pull request. I have it on my todo list to bring in some new stuff and updates from other projects. It's just kind of low on the todo list. :)