[WIP] Fixing up analysis so that it builds

[birkenfeld]

First step: trav_monad and dependencies

In contrast to the parser monad, I decided to de-monadize the TravMonad and instead make it a traditional mutable struct with Result "throwing" methods. A monad action for runTrav is now a closure that takes a Trav object and mutates it. I think that should cover what we need.

ref #9