Merge pull request #6 from ioerror/master

Add xep-0136 anti-data retention action
Revert "add otr field"

This reverts commit 8c7cdf838fe9dcb1e8f966baf8e5fb611621235a.
Sadly, absolutely zero jabber servers I tried to use will work if this code is enabled.
I guess we might try to be smart about it - this however allows the client to work at all
on those respective servers. Sigh.