Added a test for percent adult obesity.
Added algorithms and tests for adult diabetes and fitness center per capita, both on a county level.
Added a lot of new data from the ERS, and rewrote loading.py so that new fields can be added very easily.
Also set it up to import all of the new ERS data.

To Do:  Write Algorithms for ERS data.
Merge pull request #29 - ERS data and algorithms by harbieism