This is a hack of parserm.h from the Inform 6/7 library to support timed input.
It won't do to create Freefall or anything - it's intended for Border Zone
style games.  Also included is a brief demo program (which was the beginning of
a planned full game with a two hour time limit, and the reason I wrote this).

To use this hack, simply include this version of parserm.h instead of the
standard.  This will probably not work under a version other than 6/7.  See the
comment block at the top of parserm.h for further instructions.