cross() function exists in OpenSCAD core language

[clothbot]

Hi Oskar,

I don't remember when exactly cross() was added into OpenSCAD - it's been several years since my initial add of linear algebra support and Marius' full re-write - but it makes this (re)definition obsolete:

https://github.com/OskarLinde/scad-utils/blob/484d39bc2fd19cf6903c8e92e01af40a77276e66/linalg.scad#L3

See docs: https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/The_OpenSCAD_Language#cross

Andrew.