[multi part] Gesture Multi-Select feature.

Couple of side changes:
1. Moved Long Press event to UserInputHandler level. Removed weird
LongPressListener that was lingering in DirectoryFragment.
2. Set RefreshLayout to never intercept events.

Bug: 30101739
Change-Id: Ib1c90f372850200293c366eb406a861853aee628
9 files changed