enable unittesting

[benoitc]

It's hard actually to test rcouch (so is couchdb). And js tests aren't reliable, The situation should be improved asap in couch_core.

I see different steps before having a fully well-tested rcouch version:

1. enable current unit-tests from couchdb in the command line. and update the travis configuration accordingly
2. Each issue should have test to reproduce it. The test should be written before the actual patch lands in thie source code. Each issues should be handled in their own branch named fix/issue
3. New features should be documented first. A test based on the documentation should be written to test the actual code handling that feature. Maybe the test could be written first, or at least in // but in any case a new feature should land with that patch. Happy to discuss about the order, I'm not really a fan of TDD but maybe that could help here.

Thoughts ? cc @nrdufour @dch @tilgovi