This is a big change that break compatiblity with existing applications
*and* with existing installed versions of main.py.
When upgrading it is import to update main.py:
./tools/wasptool --upload wasp/main.py
This is something of an experiment but now the app roll is traversed using
horizontal swipes and applications should primarily use vertical swipes
to navigate internally. This is mostly because if "feels" better but it
also leaves the vertical scrolling hardware available for use by the
app.
Moving it from applications into the watch is useful for two reasons.
Firstly it means applications don't need to know as much about the
display color depth and secondly it makes it easier to replace the
drawing routines with wasptool.
