readded collision detection to environment (NOT CELLS, THAT'S NOT A GOOD IDEA)
and fixed the unnecessary arguments
Okay okay. Lots of changes here. I primarily took care of this
first implementation of Collision in response to Billy's implementaion
of collision detection, and Dalen helped with the
display.py fix - in fact, I'd go as far as to say that Dalen pretty much
dictacted the entire fix while I just wrote the code.

Okay, so here are the changes:

display.py
we changed the print(Cell.color) to just print "", to avoid printing out
each cell's color at every tick.
For some reason, when the print function is removed entirely, the program
runs extremely slowly. It seems that there's some bug in display which
requires the print statement as a sort of Duct-tape fix... macgyver style...
Dalen was pretty much entirely responsible for this
TODO: Fix taht

cells.py
I did this pretty much alone, though Dalen helped fix some syntax errors I
made in the initial writing.
Billy's initial implementation of Collision detection was really inefficient,
because each cell went through the list each tick. Now environment handles it
the collision-detection instead, which works fine.

environment.py
Collision detection is here. Right now, when cells collide, they lose all
velocity and acceleration.
TODO: delete the extraneous Tick function which appears before the
SECOND tick function. Also, implement the actual collision.
Okay so collision now works pretty well.
Most changes are in cells.py with the collidesWith(self, foe) function.
Based off of the electrostatics idea first put forward by Aaron, voted on
by everyone else, and coded completely by me (Brad Baker).
Peter Gui and Johnathan helped put forward ideas for collision,
which were not implemented.
TODO: Remove rounding which was done for safety, but may not be necessary.
commented out rounding and print statements for collision detection. It
still works.