Reviewing strategies

Here is the check list for reviewing a strategy

1. Check strategy logic and tests.
2. Check strategy names, reference and source (new reference needs to be added to: /docs/reference/bibliography.rst).
3. Check classification of strategy.
4. Check that strategy is added to all_strategies in axelrod/strategies/_strategies.py
5. Check that strategy docstring will be auto documented: module it is in needs to be listed in /docs/reference/all_strategies.rst