irc.py: tests: add test-irc-parse
irc.py: fix some bugs in tag parsing
irc.py: tests: fix tag testing
irc.py: allow passing a list
irc.py: undo last, always start with strings for test-irc-parse
irc: redo prefix parsing to use [nick, user, host, is_server]
irc.rb: implement and test IRC::Prefix