Fixing issues with maxpolydeg

[jacob-prince]

Small fixes that address the following issues:

• Error in make_polynomial_matrix #168
• Maxpolydeg related issue #166

Also, reverting changes that were made in this pull request:

• Patch for maxpolydeg parameter #171

We have verified that these changes allow the example01.ipynb script to run correctly. We will continue testing to be sure that this issue is fully resolved across all the latest versions of numpy/python.

[jacob-prince]

The error was occurring because make_polynomial_matrix() expects degrees to be an array/list of polynomial degrees, but it was receiving a single integer value. This was happening because maxpolydeg was being handled as a single integer rather than an array of degrees.

We've modified the make_polynomial_matrix function to handle both cases:

• When degrees is an array/list: it behaves as before
• When degrees is a single integer: it creates an array of degrees from 0 to that number (inclusive)

This change should fix the TypeError while maintaining the intended functionality. The function will now:

• For a single degree N, create polynomials of degree 0 through N
• For an array of degrees, create polynomials for exactly those degrees