Final release version 0.7.6

Changelog

Version 0.7.6, December 18, 2020

Per A Brodtkorb (30):
* Renamed _core.py to core.py
* Removed the module index from the appendix because it was incomplete.
* Removed nvector.tests package from the reference chapter.
* Added indent function to _common.py to avoid failure on python 2.7.
* Moved isclose, allclose and array_to_list_dict from objects.py to util.py
* Moved the following function from test_nvector.py to test_rotation.py:
- test_n_E_and_wa2R_EL, test_R2zxy, test_R2zxy_x90, test_R2zxy_y90
- test_R2zxy_z90, test_R2zxy_0, test_R2xyz test_R2xyz_with_vectors
* Replaced assert_array_almost_equal with assert_allclose in test_objects.py
* Renamed test_frames.py to test_objects.py
* Added missing functions great_circle_normal and interpolate to the nvector_summary.rst
* Moved the following functions related to rotation matrices from _core to rotation module:
- E_rotation, n_E_and_wa2R_EL, n_E2R_EN, R_EL2n_E, R_EN2n_E, R2xyz, R2zyx, xyz2R, zyx2R
* Renamed select_ellipsoid to get_ellipsoid
* Moved the following utility functions from _core to util module:
- deg, rad, mdot, nthroot, get_ellipsoid, unit, _check_length_deviation
* Added _get_h1line and _make_summary to _common.py
* Replaced numpy.rollaxis with numpy.swapaxes to make the code clearer.
* _atleast_3d now broadcast the input against each other.
* Added examples to zyx2R
* Added the following references to zyx2R, xyz2R, R2xyz, R2zyx:
- https://en.wikipedia.org/wiki/Aircraft_principal_axes
- https://en.wikipedia.org/wiki/Euler_angles
- https://en.wikipedia.org/wiki/Axes_conventions
* Removed tabs from CHANGELOG.rst
* Updated CHANGELOG.rst and prepared for release v0.7.6
* Fixed the documentation so that it shows correctly in the reference manual.
* Added logo.png and docs/reference/nvector.rst
* Updated build_package.py so it generates a valid README.rst file.
* Updated THANKS.rst
* Updated CHANGELOG.rst and prepare for release 0.7.6
* Added Nvector documentation ref https://nvector.readthedocs.io/en/v0.7.5 to refs1.bib and _acknowledgements.py
* Updated README.rst
* Renamed requirements.readthedocs.txt to docs/requirements.txt
* Added .readthedocs.yml
* Added sphinxcontrib-bibtex to requirements.readthedocs.txt
* Added missing docs/tutorials/images/ex3img.png
* Deleted obsolete ex10img.png
* Updated acknowledgement with reference to Karney's article.
* Updated README.rst by moving acknowledgement to the end with references.
* Renamed position input argument to point in the FrameN, FrameB and FrameL classes.
* Deleted _example_images.py
* Renamed nvector.rst to nvector_summary.rst in docs/reference
* Added example images to tutorials/images/ folder
* Added Nvector logo, install.rst to docs
* Added src/nvector/_example_images.py
* Added docs/tutorials/whatsnext.rst
* Reorganized the documentation in docs by splitting _info.py into:
- _intro.py,
- _documentation.py
- _examples_object_oriented.py
- _images.py
- _installation.py and _acknowledgements.py
* Added docs/tutorials/index.rst, docs/intro/index.rst, docs/how-to/index.rst docs/appendix/index.rst and docs/make.bat
* updated references.