This is an extension "wrapper" (no such C function). This allows ruamoko
programs to read property lists without worrying about the memory required
to store the string for the property list being read.
Much more testing is required (oh, but for qc-valgrind), but there is now
a ~945kB block of free data in the menu progs heap :).
Also, correct the printed size of the memory block to not include the
block header size.
