Overlapping intersect processing into slices and intersects API

[jbuckmccready]

• Transcribe from C++ code the intersect sorting/processing into organized overlapping slices
• Determine structuring for API around finding intersects

[jbuckmccready]

Overlapping intersects processing into slices is done but tests are limited, commit: https://github.com/jbuckmccready/cavalier_contours/commit/9adbe6e54cc5c071453da04198fcf70ff364548d