* The behaviors of stow and proximity sensors are pretty similar, so
there's no need to use both at the same time. Simply use the stow
sensor to handle both hand wave and pick up gestures.
* Switch to timestamp associated with the sensor event to determine the
operation while at it.
Change-Id: I39767cf7b2e48bc2b0baabfac1e47240012f71d6
276242afab