The CouchDB implementation currently does not allow + chars in the
database name.

Add support in the CouchDB implementation layer for the + char
be included as part of the database name.

Add unit tests for databases containing a + char.

Change-Id: I59001d1aed19066d65f6e230f41958cd2a8cbd73
Signed-off-by: Chris Elder <chris.elder@us.ibm.com>