lexer condition state stack fix/improvement

the lexer condition state stack was growing indefinitely (2 states per rule with action code): the new code keeps the lexer condition state stack sane as now the action state is correctly POPped off the stack when a action code block has been lexed.

Side Notes:

1)  only a few days ago did I notice that you split the jison code into multiple modules like this; I think that's good (in a way) but I work on multiple platforms, not all of which have a 100% reliable node/npm setup, so I pray you keep it down a little with the node happiness. ;-)
The 'SHA <nnnn>' commits of mine contain the work that I moved into your new submodule organization.

2) my edits are tested in a production parser. That's no guarantee there's zero errors in them, but it does mean bugs are fixed ASAP in my repo when they are uncovered.