Bug Fixes

This fixes a couple bugs that have popped up as a result of Pandas 0.15 coming out.

- We no longer need to monkeypatch patsy. A fix doing the same thing was released in patsy 0.13. (https://github.com/pydata/patsy/pull/44)
- When passing an index to `np.repeat` pass the `.values`, not the Pandas Index.

There's a remaining bug we've been discussing at https://github.com/synthicity/urbansim/commit/fc4df12161bafe80c0da9454a8da09866b486093. I'm going to let @fscottfoti have a look at that one.