Added couple of FAB behaviours

[igor-brishkoski]

@Ashok-Varma I don't know if this functionality belongs in the library, I'll leave the descision to you.
If you want to include them it, I'll cleanup the classes and make an entry to the README

[jt-gilkeson]

@igor-brishkoski The ScrollFABBehavior doesn't seem to scroll the FAB off the screen (just moves it to the bottom). If you look at the Google Plus app, they scroll the FAB all the way off the screen. May want to do another behavior for this, or fix ScrollFABBehavior if that is what is intended (the commments seem to indicate this, but it looks like mDefaultOffset is always 0?). Or maybe I'm missing some attributes on the FAB?

[Ashok-Varma]

yes but we need to modify the way they work. User should be doing all those things instead our bottom bar automatically do that. User could set the FAB style our bottom-bar, bottom-bar will manage that.

We can have a discussion about it. i am modifying a one of this commit i will see what i can do about it. To night i will do the changes. After that you can check the way it behaves, and we can add functionalities else many conflicts gonna occur. Give me 24 hours of time to merge the commits and change the codes a bit and push the change back.

Thankyou verymuch for the support

[jt-gilkeson]

Something that I've seen is that VisibilityFABBehavior doesn't handle flings - the bottom bar correctly hides and shows but the fab only works if you scroll with your finger on the screen, flinging doesn't cause FAB to show or hide.