Add new AuthVector classes
Don't update the cache for an AKA vector
Call put_av from on_digest_change
Make the cache layer use a DigestAuthVector
Add AuthVectorHandler
Disable homestead provisioning API in C3E
Plumb authtype and autn through the code
Add missing file
Merge branch 'master' of github.com:Metaswitch/crest into aka_hss

Conflicts:
	src/metaswitch/crest/test/api/homestead/backends/hss/gateway.py
Switch to using a features directory rather than a file
Fix bug in init.d scripts
HSS updates for AKA
live test fixes
Make the list of supported Cx vendor IDs configurable (but default to the spec-defined value)
Various improvements to AKA support:

* Allow interop with an OpenHSS (which requires an authentication scheme of "unknown" not "Unknown")
* Cache the realm and QoP values returned from the HSS
* Record whether SIP-Digest is known to be the preferred authentication scheme configured in the HSS, and don't use the cached digest if not
Update DB schema
Indicate authentication type consistently
Return nice 503 error when Cassandra times out
Merge pull request #118 from Metaswitch/issue117

[Reviewer: Andy] Make the list of supported Cx vendor IDs configurable
Fix typo