v0.7.2

The skimmer's jet stops flickering, for real this time

The round jet at the back of the skimmer holds its shape in Vulkan with Ray Tracing. v0.7.1 fixed one cause, but the jet kept flickering while you flew. Ray Tracing rounds the jet's five-sided rim into a circle, and it placed the circle's centre from the craft's position rounded to whole units, while the jet itself was drawn at its exact position. The two sat up to half a unit apart, a little differently each frame, so the rim's outer edge kept switching between rounded and straight. The circle now uses the exact position too. Replaying a recorded skimmer flight, the jet's shape no longer changes from frame to frame.

The same fix steadies the other round parts: the VTOL's jet, the wheels and the power generator.

OpenGL and the software renderer are unchanged.