[Finishes #75079302] Add trees to bee


![image](https://cloud.githubusercontent.com/assets/1767466/3741086/452a7b34-175c-11e4-842c-2c95b4da9ae6.png)

Goal is to make it easier to tell how many spaces you need to move. I made it more likely to have trees next to the path than elsewhere.  Brendan said he might spend some time next week exploring other approaches, but I think this is at least an improvement.
Maybe s/`nulls`/`tileChoices`?