The Sink is now in its own file, with a module to render the board.

I added the programming jig plastic part.  It looks like it fits the jig
PCB correctly, so there's not much holding me back from releasing v0.3
at this point.

The bracket previously supported PD Buddy Sink versions 0.1 and 0.2,
which were similar enough in size and shape to be able to use the same
bracket.  The current development version of 0.3 is 1 mm narrower, so
the bracket needs a change to support it.  That change has been made,
and a `board` parameter has been added to allow setting the board
revision.  Valid values are `sink_0_1`, `sink_0_2`, and `sink_0_3`.

The Sink bracket file comes with a module for a generic Sink mount,
suitable for inclusion in housings and other models.