* add code to calculate area and centroid of subpath
* change library to poly_it
* add a demo of area and centroid
* modify algorithm to consider negetive area as positive
* add code for manipulating polynomials in bezier-rs
* remove `poly_it` dependency and use custom Polynomial
* formatting floats to skip last zero
* add debug mechanism
* collect both intersection points instead of one
* fix test and cargo fmt
* apply minimum separation filtering in self_intersection and use better endpoint filtering algorithm
* remove debug mechanism and cargo fmt
* consider the subpath as closed for intersection calculation
* add documentation for polynomial.rs
* impl display for Polynomial
* make area always positive
* add missing docs
* fix test and cargo fmt
* Naming/formatting code review
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Co-authored-by: Keavon Chambers <keavon@keavon.com>
Elbert Ronnie