Add OS X metadata to make Puzzles.app searchable in Spotlight.

Thanks to Stephen Norman for most of the work, particularly working
out what all the metadata had to be in the first place. This patch is
mostly his work, and all I've done is fiddle with the plumbing that
gets the right version number into the right places.

Buildscr

@@ -18,6 +18,12 @@ in puzzles do perl -e 'print "\n\\versionid Simon Tatham'\''s Portable Puzzle Co
 in puzzles do echo '/* Generated by automated build script */' > version.h
 in puzzles do echo '$#define VER "Version $(Version)"' >> version.h
 
+# And do the same substitution in the OS X metadata. (This is a bit
+# icky in principle because it presumes that my version numbers don't
+# need XML escaping, but frankly, if they ever do then I should fix
+# them!)
+in puzzles do perl -i -pe 's/Unidentified build/$(Version)/' osx-info.plist
+
 # First build some local binaries, to run the icon build.
 in puzzles do perl mkfiles.pl -U
 in puzzles do make