Floating action button

lx-fab is a directive that create a floating action button as described in Google guidelines.

Two directives need to be transcluded: lx-fab-trigger that transclude the trigger button and lx-fab-actions that transclude the hidden buttons. The trigger button must have xl size and the actions buttons must have l size.

Parameter	Type	Default	Description
lx-direction*	string		Define the action buttons direction. Options: up, right, down, left