Giacom's suggestions + Borg HUD tweak

- Both HUD procs broken in to several smaller procs.
- Added defines so the arguments to process_data_hud() are clear.
- Several other tweaks to data_huds.dm
- Made the sensor mode defines match the data hud ones.
- Gave borgies a HUD button for sensor modes instead a verb, to be in
line with the AI.