implements #649 added two seperate method for author and commiter to VCS changeset class - switch author for git backed to be the real author not commiter
"""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')