Oversampling and support for "cutoff_curveccN", "eg_shape", and "egN_freq_lfoX"

[PythonBlue]

Reimplemented my pull request for this project at long last. Additional notes:

1. Had to rewrite a few of the test functions as well just for the sake of minimizing the build errors for sfizz_tests, even if those aren't required for the main project.

2. Partially due to note 1, I did my best at minimizing the changes I made in this particular branch for the sake of ease of merging if approved, meaning I ommitted my custom interpolation code otherwise available in my develop branch.

3. For the sake of my own needs, also increased the range of pitchMod under the Defaults.cpp file