Changed var names to something LOGICAL & more!

Changelog:
 1. Body:
  - move_to uses look_at again.
  - ispointinside renamed to is_inside.
 2. Selector:
  - Multi-selection with lshift.
  - If selected already contains the selected body, deselects it.

Issues and Bugs:
 - None that I know of so far.
TODO:
 - Multi-movement.