mark which planets have O2
vector ops
cosmetic changes: remove _ from variables
fix drag coefficient for intakes, and minor fixes

intake.dragCoeff now handles low-speed drag
renamed intake.drymass to intake.mass
AoA now in degrees rather than radians.
default deltaT now 0.04 as in KSP stock.
new module planeDesigner

planeDesigner.forces now prints out the forces acting on a plane.