v2.1.0

This release brings smaller internal changes
Please read the migration guide: https://github.com/mikepenz/FastAdapter/blob/develop/MIGRATION.md

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library

• split up into core, commons, extensions
• add GenericAbstractExpandableItem (commons)
• FIX #253
• fix unBindViewHolder method may get the wrong item from getItem()
• add type to the List payloads to fix raw-type warning
• add RippleDrawable Util (by @FabianTerhorst)
• Only animate selectable background if we want to (by @Fuhrmann )