Add support for any FloatingActionButton library

[rishirajrandive]

Any great library for making fancy FABs/ FAB menu could be used with AHBottomNavigation
The changes here:

1. Make manageFloatingActionButtonBehavior methods to generic.
2. Update DemoActivity to accommodate the changed methods. Where only one more argument is added to manageFloatingActionButtonBehavior() method, the argument is 'factor' which is used for positioning the Y of FAB or FAB menu.

[Rainer-Lang]

@rishirajrandive Clans FAB isn't maintained anymore. There are other alternative libs which are very good maintained. IMHO even in the demo there shouldn't be an old lib.

[rishirajrandive]

Thanks! @Rainer-Lang, it makes sense.
I was not aware of other libraries like Clans FAB and I used Clans FAB in my project along with AhBottomNavigation, so I ended up making this change.

[Rainer-Lang]

@rishirajrandive It's ok. Have a look here: https://github.com/jahirfiquitiva/FABsMenu

[rishirajrandive]

@Rainer-Lang thank you for the library, will this work with ahbottomnavigation?

[Rainer-Lang]

@rishirajrandive I really don't know. Sorry. But if you test it - please give feedback here or even better change your PR. :-)

[rishirajrandive]

@Rainer-Lang I checked for the suggested library, changes in the pull request work well with it. Changes in pull request are generic and not dependent on any library.