Remove extraneous functions and calls from usafacts

[sgsmob]

Fixes #419. Some legacy functions and calls were not removed from the USAFacts indicator.

[chinandrew]

I'm getting some test failures on test_pull.py, all of the form TypeError: Can only merge Series or DataFrame objects

[sgsmob]

I'm getting some test failures on test_pull.py, all of the form TypeError: Can only merge Series or DataFrame objects

I can't replicate this; did you just do git fetch sgsmob usafacts?

[chinandrew]

I'm getting some test failures on test_pull.py, all of the form TypeError: Can only merge Series or DataFrame objects

I can't replicate this; did you just do git fetch sgsmob usafacts?

Ok it was on my end, may have been on an old branch or something. lgtm