unit tests of buildbot.status.web.base.plural() method
unit tests of buildbot.status.web.base.abbreviate_age methid()
test running 'buildslave stop' with invalid basedir path
test running 'buildslave restart' with invalid basedir path
clean-up
added unit test on buildslave.util.remove_password()

Check that remove_password() handles correctly paths with '@' sign.
small simplification of buildslave.util.remove_password()