This enables both modes for TalkBack,
explore-by-touch and the normal swiping mode.
It is partially inspired by the BarGraphView example
of the Google/Android Eyes-Free project.
Note that for any accessibility to work you'll need
a device with api level 16 at least.
Using reflection we should be able to dynamically pick up
the classes if we have the high enough api level.
Reviewed-by: Eskil Abrahamsen Blomfeldt <email@example.com>