it's now possible to choose the LaRCsim model at runtime, as in
fgfs --aircraft=c172
or
fgfs --aircraft=uiuc --aircraft-dir=Aircraft-uiuc/Boeing747
I did this so that I could play with the UIUC stuff without losing
Tony's C172 with its flaps, etc. I did my best to respect the design
of the LaRCsim code by staying in C, making only minimal changes, and
not introducing any dependencies on the rest of FlightGear. The
modified files are attached.
