This fixes some DXFs imports where unforunately CAD tools like SolidWorks
randomly decide to mirror circle definitions across the "z" axis (resulting in x or y axis flips in 2d)
Most likely live projection from 3D to 2D drawings introduces this.
However this is DXF specification to describe it so obtusely with vectors for a 2d drawing.
* Split up the thirdparty code into the thirdparty folder (#3637)
* Create a new kimath static library containing all the math functions
This is part of cleaning the build system for #1906.