Fixed bogus "marked" dependency (apparently they rejigged the allowed versions).
Added "memdown" as a test dependency (we use it to make pouch work in-memory instead of on disk).
Updated to tagged version of upcoming pouch release.  Added support for PouchDB.defaults(), which has enabled us to prevent pouch from dumping content on disk.
Had to disable test for the presence of the couch _id and _rev parameters, as our pouch dependency makes it too difficult to correctly screen them out in our test.
Configured PouchDB to work in memory, which means our tests are now completely repeatable and don't dump a bunch of temporary directories in whatever directory they're started from.