Laserbeamsize

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* fix zenodo
* update CITATION.cff
* add pypi github action
* fix copyright
* correct readme to use plot_image_analysis()
* tweak badges

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* readthedocs does not do well with new module names

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* splitting monolithic m2.py
* added tests for functions in gaussian.py
* improved docstrings in gaussian.py
* improved module docstrings in m2_fit and m2_display

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* trying to get conda release working

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* change default background removal to match ISO recommendation
* split monolithic laserbeamsize module in separate modules
* rationalized functions names
* add citation stuff
* add github actions to test and update citation
* improve readme so images work on pypi.org
* add conda-forge support
* update copyright years
* more badges

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* allow beam angle to be specified during fitting
* new notebook to illustrate constrained fits
* improve docstrings and therefore api documentation
* still better ellipse and rect outlines
* start adding examples