* fix transaction wrapping bug that caused get_user_id_by_threepid_txn to fail

* towncrier

* white space

* Clean up the CSS for the fallback login form

I was finding this hard to work with, so simplify a bunch of things. Each
flow is now a form inside a div of class login_flow.

The login_flow class now has a fixed width, as that looks much better than each
flow having a differnt width.

* Support m.login.sso

MSC1721 renames m.login.cas to m.login.sso. This implements the change
(retaining support for m.login.cas for older clients).

* changelog

* Add better diagnostics to flakey keyring test

* fix interpolation fail

* Check logcontexts before and after each test

* update changelog

* update changelog

* Some words about garbage collections and logcontexts

* Do a GC after each test to fix logcontext leaks

This feels like an awful hack, but...

* changelog

Now that we use py3, compiled python ends up in __pycache__ rather than *.pyc.

Signed-off-by: Aaron Raimist <aaron@raim.ist>

Signed-off-by: Aaron Raimist <aaron@raim.ist>

* port hash_password

* changelog

Signed-off-by: Ruben Barkow <github@r.z11.de>

So people can still collect consent the old way if they want to.

fixes #4056

* Add helpers for getting prev and auth events

This is in preparation for allowing the event format to change between
room versions.