Loosen up the allowed characters in a redirect

[dariota]

This resolves #70. The negative match at the start of the redirect regex prevents redirects from starting with common bot command characters, to avoid activating other bots with redirects (as fun as that may be).

[dariota]

An alternate solution to the problem solved with the negative lookahead would be to have a prefix when redirects are used (e.g. "> Gambit!!!:" instead of "Gambit!!!:") or use notice instead.