Move Python script templates to their own directory and add .template extension.
Update setup.py to automatically find packages and to install the model templates.
PEP8 formatting for model templates.
Add test for hedonic model template and gen_model function

Also fixes to templates and gen_model function to get test passing.

First test for urbansim2, woo!
Test for locationchoicemodel template.
Test for the minimodel template.
Refactor template assertions into helper functions.
Test for modelset template.
Test for networks template.
Test for the transitionmodel2 template.
Exclude tests from installation.