add neuroml notebook in examples

[AurelienJaquier]

with a link to it in the readme

[codecov-commenter]

Codecov Report

Merging #439 (fabc57c) into master (e9c1adf) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #439   +/-   ##
=======================================
  Coverage   89.77%   89.77%           
=======================================
  Files          46       46           
  Lines        3383     3383           
=======================================
  Hits         3037     3037           
  Misses        346      346           

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