Fixed some issues where inconsistent streams of events could
be generated by the dispatcher, particularly when switching from
hovering with one device to hovering with another.
Fixed a bug where the touch pad would fail to generate a new
HOVER_MOVE following a tap event. As a result, the hover event
stream would not resume until the user touched the touch pad
again.
Change-Id: I444dce84641fb12e56a0af84c931520771d6c493