Add type hints to apavlov

[janga1997]

#808 @drvinceknight @marcharper
mypy produces two errors.
axelrod/strategies/apavlov.py:31: error: Need type annotation for variable axelrod/strategies/apavlov.py:98: error: Need type annotation for variable
It seems like an issue with mypy itself. I'm not sure.

And the local test produces errors which I don't think has anything to do with type hinting.
/home/janga/Axelrod/axelrod/mock_player.py:61: UserWarning: Simulated play mismatch with expected history: Round was (C, C) but (C, D) was expected for player: Adaptive Pavlov 2006 s1, s2, action1, action2, str(player1))
and more of the same error.

[drvinceknight]

mypy produces two errors.
axelrod/strategies/apavlov.py:31: error: Need type annotation for variable axelrod/strategies/apavlov.py:98: error: Need type annotation for variable
It seems like an issue with mypy itself. I'm not sure.

It does look like a mypy issue. I'm not sure how to deal with it. Any suggestion @marcharper?

And the local test produces errors which I don't think has anything to do with type hinting.
/home/janga/Axelrod/axelrod/mock_player.py:61: UserWarning: Simulated play mismatch with expected history: Round was (C, C) but (C, D) was expected for player: Adaptive Pavlov 2006 s1, s2, action1, action2, str(player1))
and more of the same error.

Don't worry about this, it's just a warning and not a failure. Travis triggered a failure but that was for a timeout on some of our property based tests, I've reset that so we'll see if that fixes itself.

[marcharper]

@janga1997 please add the strategy file to type_tests.sh

In Python 3.5 we cannot annotate variables, that's a Python 3.6 feature. If you are using Python 3.6 for testing with mypy you may get different results. Travis will check both once you add the file to type_tests.

[janga1997]

@marcharper I am using Python 3.5.
But I am sure a similar situation has occurred in previous commits, but it never raised an issue there.
I don't understand what is unique about this situation?

[marcharper]

I'm not sure really -- can you rebase/merge and run mypy again? I'll take a closer look at the errors.

[marcharper]

mypy is unhappy because we're using both None and strings for the same variable without declaring its type. Just change both lines to: self.opponent_class = "".

[drvinceknight]

Since #852 has been merged in there are now merge conflicts @janga1997 :)