Allow specifying PASS or SASL authentication (#77)

This allows clients to connect to password-protected servers that
require PASS or SASL authentication to connect to (e.g.: bouncers, and
sometimes IRC networks require SASL from mobile connections to prevent
abuse)
Change password to advanced setting
Merge branch 'pass' of https://github.com/errietta/fxos-irc into errietta-pass