This is needed for Rockbox's polygon drawing.

Last November in commit 08365fb260ae6e3 I added a VERSIONINFO resource
to the Windows puzzle binaries, with three of the four integer
components of the binary version number taken from the year, month and
day of the build date. The header file #define of those integers was
made by a Perl one-liner which just split up $(!builddate) into the
right groups of digits.

But it didn't trim leading zeroes. So the build failed today because
the month component of the version number was '08', which isn't a
valid C integer literal (the leading 0 means octal, but 8 isn't an
octal digit), and presumably therefore not valid according to llvm-rc
either. I have to assume that the previous months have all worked
because 01, ..., 07 _are_ valid octal integer literals and still mean
the right things.

I'm not 100% satisfied with this explanation, because surely the same
argument applied to the day field should have meant my builds failed
on the 8th and 9th of every month since I added this code last
November! But I don't have any evidence left over to show why it
_didn't_ fail. Perhaps I've upgraded llvm-rc past a relevant bug fix
in the last month, or something.

This adds a "half-grid" cursor mode, settable via a preference, which
doubles the resolution of the keyboard cursor, so that it can be over a
square center, vertex, or edge. The cursor select buttons then toggle the
edge directly under the cursor.

There are two advantages to this new behavior. First, the game can now be
played with only the cursor keys, doing away with the need to hold Control
or Shift, which are not currently emulated on Rockbox. And second, the new
interface is arguably more discoverable than the legacy mode,
which is still retained as a user preference.

This is useful on smaller screens, where the default-size pencil marks may
be too small to be visible by default.

This was breaking Rockbox builds due to the lack of vprintf().

"point"->"pointer".