Access to Z-variables through SimConnect

Thank you very much for adding L-variable access to SimConnect. Please add
Z-variables too. Direct communication between SimObjects and SimConnect
clients would simplify many things in more complex applications like the VDGS
module I’ve developed. Currently I am working on airport vehicle system, and
again, direct read/write access to Z-variables would allow direct manipulation
of model behaviors over SimConnect, greatly simplifying the overall
arhitecture.