- Turn the rest of the 'magic numbers' into named constants
- Task listing profiles
- Ensure the boxes load from the screen edges outwards (not done
  currently correctly right now)
- Add double buffered updates
- Allow more control over task grouping

- Move the generic code from Kasbar and the default taskbar to
  libtaskmanager

I'll switch from version 0.8x to 0.9 when I fix the max boxes bug.

