Enrich the 2-d maze environment

New requirements: 

1. Make the lava not be giant columns
2. Create a parameter for different types of tiles with reward distributions (e.g. "Water" in the range "-1 to -5", "Trees" in the range "0 to -2", "Shallow Water" in the range "0 to 1")
3. Make sure to deactivate tile after it's hit (to not cause agents to jitter back and forth into tiles)