Initial infrastructure changes

Corpus tests passing, all others not
Prod refactor complete

Prod now converts feature representations to segment lists and operates
over them
Slight symbolsim refactor

Tests pass now
Added infrastructure for discourses

Also new tests
Actual addition of new class testing
Bunch of small things

Added some documentation
Fixed some stupid API things that I wrote earlier
Fixed up tests so that they incorporate said changes
Merge in changes from Scott
Merge pull request #191 from kchall/infrastructure

Infrastructure updates