It's a USB Type-C connector just like the one used in v0.1 and v0.2, but
with only SMT pins (except the fixing pins, of course).  They're
slightly cheaper and probably nicer for automated assembly, but
impossible to hand-solder.  That's okay though: where we're going, we
don't need hand-solderability.

They won't be installed by default, so there shouldn't be solder paste
applied to their pads.  To that end, I copied the footprints to the
pd-buddy library and removed the paste from all their pads.

The switch is optional, no components need to be removed when it's
installed, and there's no zero-ohm jumper.  This circuit has been tested
on a modified v0.1 board, and it works fine.

The LED does a lot more than indicate that power negotiation failed, so
its name has been changed from NOPWR to Status.  The boot mode switch
doesn't need to be yelling, so its name is changed from BOOT to Boot.

Google likes the name better this way.  Plus, it provides clear naming
for possible future PD Buddy products.

It was bidirectional on the Microcontroller sheet, which is wrong.  Now
it's input, like it should be.

0 Ω resistors are cheap, and switches are expensive.  It would be nice
to be able to save the price of a switch, since it's not really
necessary anyway.  I can program these by SWD, after all.

I added a 0 Ω resistor, R11, to pull the BOOT pin to ground in lieu of
having SW1 installed to do the same job.

I had the source and drain reversed—whoops.  After fixing it with an
X-Acto knife and some point-to-point wiring, I've updated the schematic
and PCB files accordingly.

THIS ALSO MARKS THE BEGINNING OF DEVELOPMENT OF THE NEXT BOARD REVISION.

Tested to probably not blow anything up if assembled properly!