Merge pull request #15 from MOARdV/master

Initial check-in for JSIHeadsUpDisplay.
Updated JSI HUD so the pitch ladder works.

Drawable texcoords are now [0.25, 0.75] horizontally (the middle 1/2, from 1/4 of the way across to 3/4 of the way across).  User configurable whether it's a 180 degree or 360 degree strip.