Add interval to willie.bot.is_callable.
Fix owner detection.
Fixed comparison of nicknames to assume ascii and that '~' == '^'.

str.lower() takes locale into account, which could cause some nicknames
that are not equivalent to be treated as equivalent. Probably not in the
narrow character range allowed in nicknames, but better safe than sorry.
Set reload.py to be used only by owners.
Guard against unicode.
Typo fix.