add <any>, manyUntil; keyword args for many

- make `many` more "rackety" with keyword args #:till and #:<or>
- implement many1, manyTill, many1Till in terms of many + kws
add comments in parsack-tests
Merge pull request #36 from stchang/dev

Add `<any>`, `manyUntil` from `dev` branch for issue #34