Behaviours adding/removing working.

Not sending what behaviours are currently active on a creature yet.
Next: need to use the class.getConstructor() thing instead of
newInstance(), and get rid of this silly empty constructor business.
Updates to generics so compiles with less errors; using constructor
creation properly for body; must still do limbManager.
LimbManager now using the correct constructor type instantiation.
All creatures besides worm, now updated to new PShape thing.
Appears that reinitialising of behaviours is working: especially for
PBox2DBehaviour. 

Will have to test with all creature types however.
Worm now working. Fixed up how Creatue update() is called.

Other stuff I'm sure.
Feeler Manager updateDynamicPosition working without crashing.
Many behaviours now working, including FlwoField and StayWithinWalls
(although this needs a better implementation: perhaps a steering ONLY
when its near wall boundaries, and not at any other time).
Merge pull request #1 from zlot/forces

Merge Forces into Master