Adds registerUncouchableType, tweaks logging.
Update .travis.yml to include services: couchdb
Removes the ascii requirement for strings to be packed into json natively.

This will result in utf8-encoded binary strings to round-trip and come back as unicode, but if that's an issue, I'm not sure if the choice of a JSON-backed DB was a wise choice.
Other binary should be picked as per before.
v0.4.0
Fixed up the release script to use git flowisms.
Merge branch 'feature/add_register_uncouchable'
Added timeout param that gets passed into Session.
v0.4.1