Also use sed to remove now unneeded Vim lines, 2to3 -f ws_comma to fix
some whitespace, and fix some other madness manually.

also use 2to3 -f ws_comma to fix some whitespace

holy diff batman!

print archving negotiation result in chat control

Now we do:

contact.supports(feauture) instead of gajim.capscache.is_supported(contact, feature)

 - when a new contact with higher prio connect, detach session from chat control. Fixes #5021
 - don't re-use a session that was for another sessin

Tests are more than welcome!