add tests for VCSRepo.log(firstparent=True)
correctly handle SvnRepo.log(firstparent=True)
add tests for VCSRepo.log(merges=True) and .log(merges=False)
add tests for VCSRepo.log(path=something)
almost correctly handle SvnRepo.log(path=something)
add more tests for VCSRepo.log(path=something)