Modify/fix initial play of lookerup players.

[drvinceknight]

Closes #1185

Currently, the lookerup players pop from a list of initial plays. This
breaks when playing against the cheating players which simulate their
play (as the list of initial players no longer exists).

This fixes that by ensuring the list of initial plays does not
disappear which I think technically is probably better behaviour anyway?

[marcharper]

Looks fine assuming the Appveyor build finishes successfully.

[drvinceknight]

Looks fine assuming the Appveyor build finishes successfully.

The failure is related to #1187, I'm actually beginning to suspect that has to do with the Human player and prompt toolkit. I'm seeing if I can figure that out, but a simple fix might just be to remove the Human player for now.

EDIT: Almost certain it is not the Human player.

[drvinceknight]

As far as I can tell it's not possible to rerun branch builds on appveyor (as opposed to PR builds). So I suggest this is merged @marcharper, I've opened #1191 to try and identify what is causing the issue.

[drvinceknight]

I'm labelling this as ready to merge as I do not see how to restart the branch build on appveyor (I'm continuing to see if I can figure out #1187).

[marcharper]

You can start a new build with the "Play" icon button on Appveyor.

I think that the error may be due to matplotlib and our after tournament plots. I've read elsewhere that using matplotlib.use('agg') may help. The default backend is tkAgg (tkinter), which uses Tcl.

Alternatively we could suppress "showing" the images in the test suite, which I think could fix the issue.

[drvinceknight]

You can start a new build with the "Play" icon button on Appveyor.

I'm used to that Play button and have used it many times on PR builds but as far as I can see it doesn't exist on specific commit builds, I spent a long time double checking that but if/when this happens again, you could screenshot where it is on a commit build that would be awesome. 👍

[marcharper]

I just clicked on the Details link for "continuous-integration/appveyor/branch AppVeyor build failed" above and the page that it takes me to first has the Play "New Build" button showing. Maybe you were signed out or signed into a different account and couldn't see it for some reason (I had to sign in with github to see it).

[drvinceknight]

Yeah it seems to be there sometimes and sometimes not (???).

The build link from the failed thing:

https://ci.appveyor.com/project/marcharper/axelrod/build/1.0.330

Gives me:

Not important.