Added option to avoid deceleration [1.0.0]

`BOOL decelerates` property added to the header, set YES by default. If its set to NO it will stop right when you stop dragging.

I made this trying to increase 'magnet force' on the scroll, but I didn't achieve it. Anyway, I prefer that than slow decelerating in my use case.

Also, I created a tag, and a LICENSE file (according to the license seen in cocoacontrols) in order to create a podspec. 

If you accept this pull request, I will add it to CocoaPods :smiley: