return the Facebook error in the str representation of the AdsAPIError
fixed how bid_info is sent when creating adgroups
Merge pull request #12 from GallopLabs/feature/exception-str-message

Show Facebook error in the str representation of the AdsAPIError
Merge pull request #13 from GallopLabs/bugfix/bid-info-format

Fixed how bid_info is sent when creating adgroups
Bump up version to reflect bug fixes.