changed map to list relation, because maps have no sorting (for the output this is nicer)

Example for readable print function:

rascal>import \test::ProjectAST;
rascal>run();
								classes		methods		fields
from				to				+	-	+	-	+	-
|project://GuavaRelease01|	|project://GuavaRelease02|	1	0	81	0	2162	36
|project://GuavaRelease02|	|project://GuavaRelease03|	0	4	8	0	205	55
|project://GuavaRelease03|	|project://GuavaRelease14.0|	196	2	129	6	4220	687
|project://GuavaRelease14.0|	|project://GuavaRelease14.0.1|	0	0	0	0	0	0
|project://GuavaRelease14.0.1|	|project://GuavaRelease15.0|	12	0	19	4	553	629
added guava projects 14, 14.1 and 15