Hide dangling underscores; JSLint considers these a problem
and the command line build fails as a consequence when they
are present directly in the code, but CouchDB provides these
so we cannot avoid them entirely. So, hide them behind
variables and use []-style lookup.
Concludes transition work for the CouchDB persistence adapter,
WTD-537.
Fill in JSDoc for the CouchDB adapter which provides
the ability to persist domain object models. Part of
ongoing transition of the platform/persistence bundle,
WTD-537.
