Validate input to send-privmsg

send-privmsg now raises an error if the message contains NUL newline
or carriage return.
Merge branch 'master' of bitbucket.org:aidalgol/cunning-bot
Fix GPL copyright header notice

Added "This file is part of " to headers.
Actually fix copyright headers
Merge branch 'master' into plugins

Conflicts:
	bot.scm
	commands.scm
	run-cbot.scm