Add reader of EBSD patterns from Oxford binary .ebsp files

[hakonanes]

Signed-off-by: Håkon Wiik Ånes hwaanes@gmail.com

Description of the change

Add reader of EBSD patterns from Oxford binary .ebsp files:

>>> import kikuchipy as kp
>>> s = kp.load("patterns.ebsp", navigation_shape=(40, 50))  # (n rows, n columns)
>>> s.plot()

As far as I know, the navigation shape is not contained within the file, so that must be provided.

I hope to add a writer to this format as well, in a separate PR.

Progress of the PR

• Test reading of dummy Oxford binary file on Windows to fix failing tests
• Docstrings for all functions
• Unit tests with pytest for all lines
• Clean code style by running black via pre-commit

For reviewers

• The PR title is short, concise, and will make sense 1 year later.
• New functions are imported in corresponding __init__.py.
• New features, API changes, and deprecations are mentioned in the
  unreleased section in doc/changelog.rst.

[hakonanes]

So, the tests for the Oxford binary reader failed on Windows because I passed int to numpy.fromfile dtype parameter, and not int64, which I should have. int apparently meant int32 on the Windows test server.