Add human example script and some other fixes

[adamltyson]

This adds an example using the human atlas because:

• Now it's got both hemispheres
• The scale of the atlas makes it trickier to just adapt existing examples

This also fixes a typo and removes some script code in a submodule.

Sort of fixes #14

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (c42d3f1) to head (7c5b8d3).

Additional details and impacted files

@@          Coverage Diff          @@
##            main     #40   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files          5       5           
  Lines        285     282    -3     
=====================================
+ Misses       285     282    -3     

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[alessandrofelder]

Looks good.
While we're doing small refactorings around here that will change the API (e.g. you now can't call heatmaps.py as a script anymore), I've opened #41 as a vaguely related small enhancement issue.