optionparser -> argparse

Hey, setupYumConfig method no longer takes args. In previous version there was double parsing, now it takes parsed options from argparser.

With argparser it could be easy to accept one or more params with '--enablerepo', '--disablerepo' and '--setopt'. So instead of "--enablerepo r1 --enablerepo r2" you could write "--enablerepo r1 r2" while supporting the first one. Tell me if you want that.