hs.get_handlers() can not be invoked from split out processes. Moving
the invocations down a level means that we can slowly split out
individual servlets.

Don't change status_msg on /sync

Include prev_content in redacted state events

Clean up TransactionQueue

Measure federation send transaction resources

Various federation /event/ improvements

Don't print stack traces when failing to get remote keys

Clean up CAS login code

Fix CAS login

Fix token login

Remove some apparently unused code.

Clean up parse_cas_response, mostly to catch the exception if the CAS response
isn't valid XML.

Attempting to log in with CAS was giving a 500 error.

login with token (as used by CAS auth) was broken by 067596d3, such that it
always returned a 401.