Post-jam updates

Updates and improvements from comments and feedback post-jam.

• Added a mouth to indicate the front of the ciliate.
• Switched to time-based eating to make damage and health increases more even
• Enemy ciliates now change targets based on distance and randomization periodically
• Damage dealt is now based on size
• New damage system makes it more difficult/impossible to damage ciliates larger than yourself
• Rebalancing damage/health