Remove support for non-UTF-8 character encodings

It’s almost 2014. Anyone not using UTF-8 by now deserves to step onto
Lego bricks every time they go to the bathroom for the rest of their
lives.
Silence warnings
Remove DCC whiteboard

Nice gimmick, but… no.
pasteeditor: add button to remove timestamps

Kind of a hack, but whatever. It’s useful when it doesn’t break.