elongated panel mount holes

[jsleeio]

add support for "long" mounting holes for more tolerant Eurorack mounting

from this ModWiggler post by abschall: https://www.modwiggler.com/forum/viewtopic.php?p=3573713#p3573713

It's a modified 3mm "long" pad creqted on the Eagle footprint editor :
-Drill Size 3 mm
-Diameter : Auto
-Milling Layer (46) Contour flush with drilled hole in order to create the oblong aperture, using the line and arc tools

Would have shared the library file, but the file extension is not supported on MW

[jsleeio]

more here: https://www.seeedstudio.com/blog/2017/09/13/how-to-output-metal-slot/