token provider cleanup

UUID and PKI tokens are peers, and PKI should not be a subclass of
UUID.  This is the start of a cleanup effort to break the Provider
into a pipeline, but done in a way that each change is understandable
on its own.

Change-Id: I0720695b91d20a675374e713fe9ac6c0d7120484
Merge "token provider cleanup"
Sync global requirements to pin sphinx to sphinx>=1.1.2,<1.2

Sync the global requirements to pin sphinx.  This addresses an issue
where Sphinx 1.2 is not building documents correctly and causing
check/gate to fail.

Change-Id: I3ecf8535bd8f8ea0ee17aabc7ad418ff31f16366