function to read linewise from the associated io channel. Rewrite irc/dcc/proxy read logic on top of it. git-svn-id: file:///var/www/svn.irssi.org/SVN/irssi/trunk@4841 dbcabf3a-b0e7-0310-adc4-f8d773084564
git-svn-id: http://svn.irssi.org/repos/irssi/trunk@3127 dbcabf3a-b0e7-0310-adc4-f8d773084564