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.
In addition to the fix (which is simple) we also modify the button handling
of the simulator because, rather by acident, it relies on the bugs in the
battery meter redraw to ensure the simulator stays active.
Migrate the filling of the line buffer into a seperate function.
This does naturally reduce the cost of the loop management but
much more importantly allows us to use viper native code
generator.
