graph: fix counting of "heads" for graph, condense graph into more narrow lines instead of trying to increase its width (past certain width produces really bad html layout)
"""Various utilities to work with Python < 2.7.Those utilities may be deleted once ``vcs`` stops support for older Pythonversions."""importsysifsys.version_info>=(2,7):unittest=__import__('unittest')else:unittest=__import__('unittest2')