Changes since calltree-2.3:

-	Much better portability by using a newer version of
	the Schily SING Makefile system

	See the changelog files for cdrtools and check what
	happened during the last 3 years.

-	Now using the SSPM (Slottable Source Plugin Module)
	system.

-	concat() fixed for architectures with 64 bit pointers

-	GUI support with option -dot (using graphviz)
	Thanks to Pietro Abate <abate@students.cs.unibo.it>

	See: http://www.research.att.com/sw/tools/graphviz/
	for more information in graphviz