Swift Package Manager & Linux Support

This release adds support for SPM. Yay!

Linux support is also implied with the removal of all dependencies.

Lastly, there are breaking code structure changes with the move from a class Delaunay to using free functions. However, this means that objective-c support is no longer provided.

Example usage:

// Before 1.0.0
Delaunay().triangulate(points)

// Current 1.0.0
triangulate(points)