doc: CITATION.cff

[mmcloughlin]

Generate CITATION.cff file now supported by Github.

Updates #114

[codecov-commenter]

Codecov Report

Merging #115 (7ee7b6f) into master (908a496) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #115   +/-   ##
=======================================
  Coverage   73.05%   73.05%           
=======================================
  Files          30       30           
  Lines        1874     1874           
=======================================
  Hits         1369     1369           
  Misses        445      445           
  Partials       60       60           

Flag	Coverage Δ
stress	?
unittests	73.05% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 908a496...7ee7b6f. Read the comment docs.