* 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
944d524f18