1. Update Motor's dependency to pymongo>=3.4,<4
2. Wrap new "collation" attributes on Cursor and GridOutCursor
3. Update synchrotests for any issues with new PyMongo tests and Synchro
4. Update Changelog, Readme, Requirements, Installing
(Note: it's just a coincidence that MongoDB 3.4 and PyMongo 3.4 have the same version number.)