Implement coordinates modules.

Description

Notes

Example of usage

Open a console, type ipython and run the following:

In [1]: 'hello world'                                                                                                                                 
Out[1]: 'hello world'

Self Checklist

Not all of the below is a must, but nevertheless it is a help.

• Included your change within the unreleased section of changelog.md
• Included documentation using numpydoc style docstrings (example)
• Included some tests that
  • Help reviewers and users understand what the code is doing (a few toy examples are helpful here).
  • Test that code changes don't result in your code running not as intended
  • Verify that simple test cases of the individual components agree with easy to independently verify calculations
• Self review of the diffs
  • Verify that no unnecessary files have appeared within the diff
  • Undergo your own review of the diff, making comments at section that you believe are worth highlighting or in need of discussion
• Ping reviewers to come and review the code

#82