E0d/makefile improvements

[e0d]

We will be using this XBlock as an exemplar for repos to meet OEP-55 requirements. It's not up to current best practice in a number of ways. This is the start of that journey :)

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@ea2ed2d). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #45   +/-   ##
=========================================
  Coverage          ?   50.98%           
=========================================
  Files             ?        3           
  Lines             ?       51           
  Branches          ?        0           
=========================================
  Hits              ?       26           
  Misses            ?       25           
  Partials          ?        0           

Flag	Coverage Δ
unittests	50.98% <0.00%> (?)

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[e0d]

@feanil I have CI working end-to-end, albeit for a meaningless test. There are new commits since your review. Let me know if you want another look before I merge.