Dave,
We have Inclusion of Winds Aloft in Flight Planning on our wishlist, we will get this added but don't have a date yet for that feature. As you note, the math is trivial it's just a matter of prioritizing the feature. With v6 we are adding winds aloft downloads, so that's one more piece of the puzzle to support this capability.
"Track" is your current track over the ground. "Bearing" is the track you need to fly to reach your destination. You can toggle the iFly between "True" or "Magnetic" north pole, but for aviation use "Magnetic" is more common.
I agree we need to add a page to our manual to describe each instrument in detail. Someone else recently mentioned this deficiency to us. We'll get that done. We're so familiar with the system here it's sometimes easy to miss gaps like that.
Thanks!
Walter