Since we want to conform to dist-spec, sometimes the gc and dedupe
optimizations conflict with the conformance tests that are being run.
So allow them to be turned off via configuration params.
New options added to configuration file to reference a public key used
to validate authorization tokens signed by an auth server with
corresponding private key.
Resolves#24
Signed-off-by: Peter Engelbert <pmengelbert@gmail.com>
