.travis.yml: add pypy3

`travis lint` said that this file still looks valid.
Fix WHO clash with external plugins (e.g. ChanTracker)
Karma: Fix Pypy3 support.

Setting db.text_factory to str gets the repr() of a bytes object, while the default text factory seems to work well on any Python version.
Factoids & Karma & MessageParser & MoobotFactoids & QuoteGrabs: Fix Pypy3 support.
Merge pull request #803 from Mkaysi/travis-pypy3

.travis.yml: add pypy3
Revert "Factoids & Karma & MessageParser & MoobotFactoids & QuoteGrabs: Fix Pypy3 support."

This reverts commit 30e03a542a4072327be006f8d607e95831850a05.
Factoids & Karma & MessageParser & MoobotFactoids & QuoteGrabs: Fix Pypy3 support (without breaking Python 2 support).
Fix capability negotiation
Merge pull request #810 from nyuszika7h/fix-cap

Fix capability negotiation
QuoteGrabs: Fix previous commit.
RSS: Remove debug output.
Merge pull request #808 from nyuszika7h/fix-who

Fix WHO clash with external plugins (e.g. ChanTracker)