Raspberry Pi 3B footprints
Added Raspberry Pi 3B footprints Footprint Issue: #2016 Symbol Issue: KiCad/kicad-symbols#1772 Drawing: https://www.raspberrypi.org/documentation/hardware/raspberrypi/mechanical/rpi_MECH_3b_1p2.pdf
Added Raspberry Pi 3B footprints Footprint Issue: #2016 Symbol Issue: KiCad/kicad-symbols#1772 Drawing: https://www.raspberrypi.org/documentation/hardware/raspberrypi/mechanical/rpi_MECH_3b_1p2.pdf