PSA was monolothic, now split, with new features, like
a DB-backed partial pipeline. FB OAuth2 version also upped.
Partial pipelines don't get cleared except when necessary.
They persist for special cases like change of browser while
still mid-pipeline (i.e. email validation step).
Refactor, cleanup, and update of a lot of small things as well.
PLEASE NOTE the new `social_auth_partial` table.
It should help catch unicode encoding problems earlier.
This also updates python-saml dependency to a version that includes a
patch for unicode strings.
The python social auth SAML page returns a 500 response when accessed
without the 'idp' query param. It should redirect to the login page if
the param is missing.
SOL-1550
