Add support for new RethinkDB terms

[danielcompton]

There are a few query terms we need to add to stay up to parity with the official RethinkDB drivers. I've seen row and expr, but there may be more as well. We need to

• [ ] check and compare the http://rethinkdb.com/api/javascript/ and find out what's missing.
• [ ] Add the missing items.

[belucid]

The link from the original post no longer works, the link is now: https://rethinkdb.com/api/javascript/

Also missing now are the set operations:

• [x] setInsert
• [x] setUnion
• [x] setIntersection
• [x] setDifference

[lukaszkorecki]

Set terms are supported https://github.com/apa512/clj-rethinkdb/blob/master/src/rethinkdb/query.cljc#L501-L522 - or do you mean missing tests?

[belucid]

Uh... yup, my bad! Missed them.

Consider my comment just an update to the doc link then. 😃