Increased max units on Map back to 7 (from 4)

Runs ok in Chrome.

- HP bars needs fixing
- lots of units need work done (some grounds units, all air units)
- Some logic may be missing, but the basics are there
- Clean up needs to happen, lots of unused vars just hanging out
- Recommend reducing the size of all units by a fraction. Could probably
implement a ratio/scale (not canvas scale!) to help with that.
- Should probably add more team colors, or something to get a good color
generator for them