Fix typespecs, update protobuf specs, fix typo,..

Fixes two typespecs
 - success() -> {ok, any()}. Some response returns JsonPropLists ( {[{...}]} form ).
 - apply_seq(): first argument to [tuple()] instead of [fun()]. I think [tuple()] is right.

Updates rethinkdb protocol to up-to-date version.

Fix typo on README.md: In last two examples, query() should be used instaed of use().


I'm missing something, please let me know.