updated polygon legend labels

Lisa and Erin
I updated code so that the polygon legend labels appear as text, which I think is what you want, based on an earlier version of the map I saw. If yes, then accept this pull request.  -Jack
![mobility_app](https://cloud.githubusercontent.com/assets/649719/5498996/92a484e6-86f5-11e4-8173-3e30822b1e2c.png)