Added OOP approach to matrices (#1165)

* Added OOP aproach to matrices

* created methods for minors, cofactors, and determinants and added corresponding doctests

* Added methods for adjugate, inverse, and identity (along with corresponding doctests) to matrix_class.py
A small bug persists that causes the doctest to fail.
After a couple Matrix objects are printed, the next one is printed in a different format.

* formatted matrix_class.py with python/black

* implemented negation and exponentiation as well as corresponding doctests in matrix_class.py.  Also implemented eq and ne comparison operations

* changed __str__ method in matrix_class.py to align with numpy standard and fixed bug in cofactors method

* removed property decorators from several methods in matrix_class.py