* Widen ball well opening in REVD BTU mod
- The ball opening had an overhang left from older versions, which
should have been removed when updating for REVC or REVD. It's now been
removed.
- The actual ball well is still smaller than the official REVD
top, but this makes it closer.
* Rebase REVD changes onto REVC BTU top
- In the previous commits I had mistakenly copied the Ploopy REVD
changes onto a REVA BTU top. This meant that the ball well was too
small if you had a REVC or REVD ball.
- Now the ball well is the REVC version, with 47mm diameter. This should
mean there's much more space for the larger ball!
- This updates the BTU top to the REV D version of the Ploopy top, which
is screwed together using self-tapping screws instead of M3 screws
with threaded inserts.
- This is untested so use at your own risk. There may be another change
brought in with REV D that I've missed, and not copied into the mod's
REV D.