Made the GLWchart to plot time taken by various renderings.

Specifically, F15 looks to take too much time to render in certain
runtime environment (Core i7 860 with 12GB RAM) with even a single
instance.  It may be something to do with memory management.  Probably
we should make out something to enhance the performance, but for the
time being, measuring the current phenomena is a good starting point.
surface: Refined HUD of F15 a bit.

Now it looks like more realistic than before.
surface: Moved F15's Velocity Vector to drawCockpit from drawHUD.

The drawHUD() function is not really rendering Head Up Display in case of
aerial vehicles.  If it were a Head Mount Display, we'd continue to use
drawHUD() and fixing bugs in there, but we need to render the marker in
drawCockpit just like other HUD elements.
surface: F15's auto pilot turn around to get closer to the destination.