* Add JLCPCB order ID text to Six-Slot Adapter; you can select "specify location" for order number location when ordering from JLCPCB. It is placed so the SNES slot covers it. (PCB revision not incremented because it is only a minor change to the silkscreen.)
* Added relative path for footprint and symbol libs to six-slot adapter project files.
* Added footprint details/links to schematic symbols.
* Added .gitignore and included most of the files that should remain local-only.
