Unfortunately, it's still premature to start a separate header file for
display-space coordinates like I'm doing with Shuusou Gyoku. What does
make sense, though, is moving the display-space vector types next to
the display-space scalar types in `pc98.h`. This makes much more sense
than keeping them in `master.hpp` just because master.lib also has a
Point type. Would have thought that this lets us remove more than two
`master.hpp` inclusions, though…
Part of P0240, funded by JonathKane.
