Implement "do"

http://www.rethinkdb.com/api/javascript/#do

I have looked at how the [javascript](https://github.com/rethinkdb/rethinkdb/blob/next/drivers/javascript/ast.coffee#L198) and [python](https://github.com/rethinkdb/rethinkdb/blob/next/drivers/python/rethinkdb/query.py#L20) drivers implement `do` and they implement it with [funcall](https://github.com/bitemyapp/revise/blob/master/src/bitemyapp/revise/query.clj#L611), however, I can't figure out how to actually use `funcall` from revise.

Start with src/bitemyapp/revise/query.clj around the referenced funcall implementation, then compare it with the JavaScript ast.coffee and Python query.py implementations linked in the issue. Confirm how RethinkDB's documented do term maps to the existing query API; done means do is implemented and its behavior is verified against that documentation.

Written by the indexing model from the issue text.