Add more FAB options

[georgi-neykov-hub]

@kobakei, I have added more view attributes for more control apperance of the views inside FabSpeedDial and a few other modifications:

• Optimize the menu XML layouts to reduce unnecesary nesting of the View hierarchy
• Allow setting-up the use of useCompatPadding for FABs
• Allow adding an elevation to the mini-FAB label views
• Fix layout issues for portrait mode with longer text labels (use RelativeLayout, add ellipsize, and maxlines)
• Remove the default "+" icon shipped with the library