Added isort, ran isort on all files

[akash-suresh]

Resolves #1326

@drvinceknight I have added an isort config, and run isort over all the files.

Let me know if there are any modifications needed in the .isort.cfg file.

[drvinceknight]

The CI has failed with the following traceback:

************* Module axelrod.strategies._strategies
29
axelrod/strategies/_strategies.py:81:0: W0611: Unused Cycler imported from cycler (unused-import)
30
axelrod/strategies/_strategies.py:81:0: W0611: Unused EvolvableCycler imported from cycler (unused-import)
31
axelrod/strategies/_strategies.py:118:0: W0611: Unused Gambler imported from gambler (unused-import)
32
axelrod/strategies/_strategies.py:153:0: W0611: Unused HMMPlayer imported from hmm (unused-import)
33
axelrod/strategies/_strategies.py:166:0: W0611: Unused LookerUp imported from lookerup (unused-import)

Let me know if you'd like me to take a closer look and figure out what's going on.

[akash-suresh]

@drvinceknight I have fixed the issues. 😄

[gaffney2010]

This is a nice change!

[drvinceknight]

This is great!

It would be nice to add a check to the CI so that imports don't get "unsorted" in the future.

In https://github.com/Axelrod-Python/Axelrod/blob/master/.github/workflows/config.yml could you add:

    - name: Check imports are sorted
      run: |
        python -m pip install isort
        python -m isort --check-only

[drvinceknight]

Note that when/if we get to #1312 it's possible that the isort and black checks contradict each other (I mentioned this at #1326) but we'll cross that bridge if/when we need to and for now it would be good to have a check for isort 👍

[akash-suresh]

This is great!

It would be nice to add a check to the CI so that imports don't get "unsorted" in the future.

In https://github.com/Axelrod-Python/Axelrod/blob/master/.github/workflows/config.yml could you add:

    - name: Check imports are sorted
      run: |
        python -m pip install isort
        python -m isort --check-only

Done! 😄

[drvinceknight]

Fantastic, thanks for the contribution @akash-suresh 👍