Fix for issue 1463 (YASim underestimates off-axis aerodynamic forces on fuselages)

Fix for issue 1463 (YASim underestimates off-axis aerodynamic forces on fuselages)

Change the drag coefficient for fuselages along the Y and Z axes
(i.e. perpendicular to the fuselage's main axis) to use a fixed
value of 0.5. (The value can still be adjusted using the fuselage's
"cy" and "cz" XML attributes.)

For the Y-axis and Z-axis drag on fuselages, YASim originally used
a drag coefficient equal to:

	(solver drag factor) * (fuselage length/width ratio)

This value turns out to be way too small for well-streamlined
aircraft, even those with long, narrow fuselages, and especially
so for those with short, stubby fuselages. Such fuselages are
streamlined in the X direction, but not along Y or Z.

0.5 is only a ballpark estimate, but it's reasonably close for the
common case of a fairly long fuselage with a round cross section. For
flat-sided fuselages, a larger value should be used, up to a maximum
of 2 for a slab-sided block. For short fuselages, the value should be
reduced to account for end effects. The fuselage's "cy" and "cz" XML
attributes can be modified to make such adjustments.

This fix won't affect straight flight much, but it should have a strong
impact on some maneuvers. For example, it will make slips more
effective and may make knife-edge flight easier on aerobatic aircraft
which should be capable of it.

Only aircraft which specify version="YASIM_VERSION_32" or newer are
affected.