Try to use faster c json library. Fall back to simplejson.
Try to use faster c json library. Fall back to simplejson.

ssaavedra/couchdb-python,gcarranza/couchdb-python,erikdejonge/rabshakeh-couchdb-python-progress-attachments,hdmessaging/couchbase-mapping-python,jur9526/couchdb-python,oliora/couchdb-python