Remove (internal) username from messages to peer

account.name is not necessarily meaningful to the other party and may
leak information that is not supposed to be public.
Remove unneeded space
Use new default url (https) in query message
Merge pull request #46 from tribut/dont-send-name

Don't send username to peers
reveal used macs only once

without this, messages get larger the longer an otr session stays
active. this leads to anti-spam measures being triggered (on ICQ for
example) and is also the cause for the infamous bug mmb/weechat-otr#17
Merge pull request #49 from tribut/reveal-once

reveal used mac keys only once
Merge branch 'master' into instag
potr.context documentation