BAPS: Add direct library item loading.

Also clean up a bit of the handler code.
Add handle_hash and friends.

The protocol for handle_url has also been changed to a symbol; this breaks the
BAPS driver until this can be fixed.
Add method for combining new and merge! in hashes.

This comes with its own spec.
Add specs for Baps::Requests::Request.
Generalise request functions to take multiple args

This should make things more concise in the handlers.
Create the PayloadProcessor.

This factors out the handling of payloads for both PUT and POST, both as in
stripping off an index->item wrapper and as in deciding whether the payload is
a URL, a hash representation, to be sent for forwarding to another handler, or
invalid.

This is part of the forthcoming move of the handler architecture to a
driver-neutral zone.
Creating new authentication system.

This involves 2000% more classes than previously, is probably too
over-engineered, but uses method objects like there's no tomorrow.

Some other breaking changes seem to have been scooped up in this.  ARGH
Huge partly unfinished handler refactor.

This is in progress, but mainly involves the object-isation of several things
that were plain data, as well as the introduction of method objects here and
there.
Removed unreachable specifications.
Remove more unused specs.
Mass Rubocop and cleanup.
Tidy up PrivilegeSet.
BAPS: Clean up Connection.
Accidentally broke privileges.
Varied clean-up, privilege method removal etc.
BAPS: Move responder to responses.

This is partly for symmetry with requests/requester, and also in preparation
for adding handlers to responder.
Begin replacing X_do with driver_X.