m_filter Use case insensitive compare for exempted targets, add typedef for the set
m_filter Rename exemptfromfilter field to exemptedchans, use std::set::count()
m_filter Rename config key used in exemptfromfilter from "channel" to "target", but keep compatibility
Redirect the reader to filters.conf.example for advanced filter configuration
m_filter Allow exemption of messages sent to nicks specified in <exemptfromfilter> tags

Issue #655