Updated presentation

[James Carlson]

I've updated the presentation in preparation for this weekend's class.
The changes are mostly minor editorial updates to address issues
discovered in last weekend's class, but I did add a separate section to
deal with basic aerodynamics for angle of attack and load factor.

http://www.workingcode.com/UAS/

-- 
James Carlson         42.703N 71.076W         <carlsonj at workingcode.com>