Update README file with information about release 0.4

Update Changelog and fix formatting in some docstrings.

Release 0.3

Update Quaternion and ReadMe

- Add Quaternion class.
- Add easy versioning.
- Add tests in __main__ guards of submodules.
- Remove R2q from orientation.py to advocate for methods of class Quaternion.
- Update readme with quaternion and DCM examples.