Pymatrices

Added functioning of `in` operator.

- Renamed the following functions:-
- `pm.determinantOf` as `pm.determinant`.
- `pm.eigenvaluesOf` as `pm.eigenvalues`.
- `pm.eigenvectorsOf` as `pm.eigenvectors`.
- `pm.inverseOf` as `pm.inverse`.
- `<Matrix Object>.primaryDiagonalValues` as `<Matrix Object>.primaryDiagonal`.
- `<Matrix Object>.secondaryDiagonalValues` as `<Matrix Object>.secondaryDiagonal`.
- Updated PyPI Description Notes. [Refer Here](https://pypi.org/project/pymatrices/0.1.0/).

- Added the **subscription** property [Refer Here](https://pypi.org/project/pymatrices/0.0.9/).
- Changed `positionOf` to `position`.
- Improved `eigenvectorsOf()` function.
- Improved Description [Refer Here](https://pypi.org/project/pymatrices/0.0.9/).

**Opitmised `pm.eigenvaluesOf()` function.**

**Removed a bug from `pm.eigenvaluesOf()` function.**