Seen: Allow wildcards for @seen.
ChannelLogger: Fix Python 2 compatibility.
Add command to do specific command on all networks

Helps with Announce and other commands that may be need to go multiple networks.
Fix cmdall / Add the wrap()
Fix coding style and remove unneeded command
Fix incorrect error on loading nonexistent plugin
Merge pull request #548 from GLolol/no-such-plugin

Fix incorrect error on loading nonexistent plugin
ChannelLogger: Fix Python 2 compatibility.
ChannelLogger: Fix Python 2 compatibility (again).
ChannelLogger: Fix Python 2 compatibility (again).