* 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.
This also finishes the polygon with 45° lines when chosen as a create
option.
Fixes: lp:1833673
* https://bugs.launchpad.net/kicad/+bug/1833673
(cherry picked from commit fccce265aa959f5f234d32dcd29e01c1f25bd9a5)