Adjust the coloring on shield accessory descriptions
General code and shield clean-up

- Turn MonsterPosition into a generalized Position struct and use it to store
  the player's position when the TEW-11 fully charges.
- The Flan can share its' explosion function for both full charge and depletion.
- Remove the now unused powerup token handling since the shield powerups don't
  show up on the HUD anymore so there's no need for stupid SBARINFO hackery now.
- Remove all of the unused accessory fields since we don't use them anywhere.
http://tinyurl.com/pc5wlgb