TUnixSystem and TRint for printing of *** Break *** message. This allows to
also see the break message in the logs in proof and to terminate in case one
desires so. Also made the message size dynamic (solves Yves S. problem).


git-svn-id: http://root.cern.ch/svn/root/trunk@5614 27541ba8-7e3a-0410-8455-c3a389f83636