Urbansim-templates

- adds support for passing multiple tables of interaction terms in large MNL
- enables on-the-fly creation of output columns in small MNL

- allows join keys to be used as data filters in MNL simulation

- fixes an OLS simulation bug that raised an error when the output column didn't exist yet
- implements `out_transform` for OLS simulation

- fixes a string comparison bug that caused problems with binary logit output in Windows
- adds `model` as an attribute of large MNL model steps, which provides a `choicemodels.MultinomialLogitResults` object and is available any time after a model step is fitted
- enables on-the-fly creation of output columns in large MNL
- fixes a large MNL simulation bug when there are no valid choosers or alternatives after evaluating the filters
- moves unit tests out of the module directory

- fixes a bug with interaction terms passed into `LargeMultinomialLogitStep.run()`