Axelrod: 1.2.0

New strategies and some minor improvements

- Naive Prober: https://github.com/Axelrod-Python/Axelrod/pull/629
- Gradual: https://github.com/Axelrod-Python/Axelrod/pull/627
- Soft grudger and reverse pavlov:
  https://github.com/Axelrod-Python/Axelrod/pull/628

Minor improvements include:

- Progress bar for result set reading of data:
  https://github.com/Axelrod-Python/Axelrod/pull/618
- Prob end tournament players do not know match length (this was in essence a
  bug): https://github.com/Axelrod-Python/Axelrod/pull/611
- Doc fixes

Here are all the commits for this PR:
https://github.com/Axelrod-Python/Axelrod/compare/v1.1.1...v1.2.0