REL-2118: F2 TPE NPE

Drawing the science area at the offset position for Flamingos 2 is failing with a `NullPointerException` because the information it needs to do the drawing has not been initialized.  This is a "how did this ever work" situation fixed by mimicking the behavior of the GMOS science area feature.  Namely, calculating the necessary information before attempting to draw.
That's a very good point.  Looking at it now there is a lot of overlap.  I'm a bit nervous about sorting that out now though because I'm not sure whether the order of the stuff that F2 adds matters. It comes mostly in the middle of what the base class does.  Also, the call to `_iw.skyRotate` is mysteriously commented out and done in another way, presumably for some reason.  The upshot: you're very much right this is a mess but fixing it is more aggressive than I am willing to be at this point.  We could make a task for it, but in reality the whole thing just needs to be rewritten.