Compatibility with interface changes in parcel model

[pksohn]

These changes come out of changes to how urbansim_parcels calls the pro forma model. Addresses #10.

.travis.yml

Changed Travis build for this repository not only to run py.test, but also to clone the urbansim_parcels repo and run simulate.py to make sure the whole system is working.

sqftproforma.py

• Add several configuration items to attributes in the SqftProForma object. See here. These are also added to the constructor method, get_default method, and to_dict property
• Remove configs from parameters for lookup, since they are now object attributes that can be called directly.
• Add handling of simple_zoning to the lookup method. This used to be in the parcel model here.
• Add handling of residential_to_yearly to the lookup method. this used to be in the parcel model here