Oh dear, there was a bunch going on here. Firstly the move from int
to long long int for ValueFromString() means that we were no longer
catching overflows (as we were C-style casting it back to int in many
places). But even when the overflow is caught, it would run in to
wxWidgets' empty string bug while trying to log it.
Fixes https://gitlab.com/kicad/code/kicad/issues/12577
* 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.