Remove exp.txt

It was in by mistake
Update backlog
Allocate 4Gb to the JVM heap by default

This means that the program will crash if you don't have enough memory
on your machine. Still better than having to specify heap allocations
parameters every time you run a long experiment.
Add histeresis to target direction

The creatures' mouths now cannot point in the opposite direction of
their head. This hopefully fixes the problem with creatures pointing
their mouth backwards, but moving in the same way they'd move if the
food was straight in front of them. This last issue is a side effect of
the way skewing works: if food is behind you, then you have no skewing
(as opposed to maximum skewing, which you get when food is to your
side).
Search food in Space
Move all food into Space
Move nearest neighbor search to Space
Add watchdog for excessive creature speed
Fix length bug in Segment
Move collision detection to Space
Recalibrate collision detection

After fixing segment length bug