* 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.
When plotting in Eeschema, various elements may be filled with either
the foreground or background colors. The fill mode is rather unique,
requiring un-stroked pie wedges for arcs and both closed and open filled
polylines.
Fixes: lp:1840769
* https://bugs.launchpad.net/kicad/+bug/1840769
(cherry picked from commit 213547f545)