This adds a keepout area around the ground plane underneath the IC, to
try and prevent it from migrating during reflow.
Signed-off-by: Sean Cross <sean@xobs.io>
evt1 and evt2 were never produced. They also would never have worked,
because the USB connector was drawn mirrored.
Remove these and replace them with a single `evt1` that was actually
produced.
This reflects the fact that the `evt1` boards actually say "EVT1" on
them.
Signed-off-by: Sean Cross <sean@xobs.io>
