initial steps towards spline support
Merge branch 'master' into splines
Merge branch 'master' into splines
Add ability to build a subset of terms.

Esp. useful for things like graphing fitted splines.
TODO -> TODONE
Merge branch 'master' into splines
checkpoint -- wrote a bunch of code and tests, haven't tried running them yet
old stateful.py tests working again
add note about optional scipy dependency
attempt to build scipy on travis; pushing to see what happens
working bs()
make bs() public