Circle of Life

After a number of very fun behind-the-scenes coding that you will probably never see but that I am still very happy with, Build 2.0 is completed!

Changelog:

• Added alphanumeric genes.
  
• Added toggle genes (a single gene that provides a set of 6 yes/no values).
  
• Added prey preferences. Creatures will only attack critters that fit ALL of their preferences. (If two preferences are mutually exclusive, only one must be met.)
  
• Added a gene to control how hungry a critter must be before it decides to look for food.
  
• Added the food tank. When the food tank is empty, food pellets will not spawn.
  
• Plants now start at 20% health and heal up to full health over the course of their lifetime.
  
• Fixed a bug where, instead of combining the genes of both parents, the breeding process would return an exact copy of one parent's genes.