Refactor: changed config parser exception
Fix: Corrected hyperopt import statement in tpe.py
Fix: removed unnecessary character
Refactor: Better error message for config loading in run_instance.py
Refactor: Issue #16: Replace optparse by argparse
We can now override config.cfg

Overriding config is possible for parameters from the DEFAULT
section. I will open a new issue so that it will be possible
to override parameters from the other sections.