Moved CouchDb into master and upgraded RavenDb.Client

Moved the CouchDbRepository project on to the master branch since it
passes all the integration tests.  It's not yet ready for prime time so
we won't make a NuGet package yet, but it's working well it seems.  I'm
sure the LINQ provider will need to be expanded to cover other things as
we move forward with it, but the basics seem to be covered.

Upgraded the RavenDB Client to the latest.
Updated nuspec file with updated description
Consolidated the RepositoryTypes into properties

The array of RepositoryType enums was being used in multiple places, 2
for all repository types and 2 more for just those repositories that
support compound keys.  So I moved them into properties so we can just
add to one place for each