ports/opt (3.0): [notify] screen: update to 4.2.1

commit e8c8c2d1f2015f435be66493b9fbccc532a03f4c Author: Juergen Daubert <jue@jue.li> Date: Wed Apr 30 17:39:34 2014 +0200 [notify] screen: update to 4.2.1 Note: ----- Users of the screen program will not be able to reattach older instances after upgrading to version 4.2.0; this is due to upstream having made a lot of changes to the internals, and switching from named pipes to sockets for communication. Please ensure your current screen instances are not anymore needed before upgrading.