Tiny Tapeout FPGA demo board checks

• fpgas-verify: the Tiny Tapeout demo boards: how the check tells which board it has, and what its tests judge.

• fpgas-verify: what an Arty, NeTV2, Fomu or TT FPGA check tests: what each test of the check does, and when it passes.

• How to install the Tiny Tapeout FPGA packages: the check on the host, and how to run it by hand.

• Tiny Tapeout FPGA demo board test designs: the designs under designs/ and the scripts that load them.