The start state should be... a start state!
Only dump verbose things if VERBOSE_DEBUG is set.
Clean up protobuf->NFA parsing.

I'm about to make some changes to how we parse certain NFAs; these changes will be painful unless I first refactor the NFA parsing code.
Add the 'ReferenceVector' typedef.
Reference the struct, not the field!
Let states, transitions track of var references.

Each state should know "what variables have been referenced by this point in the automaton execution" and each transition should known "which variables do I reference".
Oops: copy-paste error from some time ago.
Add a (fairly trivial) assertion.
Whitespace.