require POST method for login (see #10)
use error UX instead of alert()
implement logout via XHR (POST "null" assertion, fixes #15)
Merge commit '93648a65ef90d6367fefdd781c2359a2f43d9caa'

Conflicts:
	src/mod_authn_persona.c
Merge commit '28008ae551eb966590bd1da1e6613f9f25156d5b'
Merge commit 'ff398aefa24989c82cd012af6d95c2e7f2c3e3e3'

Conflicts:
	src/mod_authn_persona.c