Fixed yaw-pitch-roll rotation conversion functions.
Fixed yaw-pitch-roll rotation conversion functions.

These where off from the proper interpretaiton of yaw-pitch-roll
(as used in the POS file format) by a 180 degree rotation about Y.
This commit corrects that interpretation and also simplifes some
of the math.

linus-sherrill/maptk,linus-sherrill/maptk,linus-sherrill/maptk,linus-sherrill/maptk,linus-sherrill/maptk