All unit tests written except chain and chainl. Removed left_factor_action, we'll handle left-recursion with our caching strategy.

Fixed inconsistent signature of charset parser, registered (still stubbed) unit tests so the build doesn't break :)

Conflicts:
	NOTES

Fixed build (completed butnot combinator). Also, fixed bug where sequence wasn't bailing out if one parser failed.

All sorts of makefile hacks, plus a new fastpath for the bitreader 

Parsers for sequence and choice are done. Got rid of join_action, we didn't need it. parse_result_t now contains a single parsed_token_t (and whatever we decide to jam into it later), so that sequence makes sense.