Add PCB trace antenna for 2.4GHz
according to TI DN0007 Inverted F Antenna reference design
Add LP2950 and SP3485 symbols
Add various RF footprints
2450FB15L0001 (balun for ATmega356RFR2)
uFL SMD antenna connector
Add Neutrik XLR3 male & female footprints
Add various standard footprints :
QFN64
SOD323
SOT6
AVR ISP header
PTC 1812