v0.6.0

A few changes to how controls are configured, making it easier to reuse control configs, as well as being easier to extend the control system.

Added option to limit AeroInfluencer actuation speed.
Allow control smoothing with external control inputs.
Added control input easing.
Added per-influencer easing values.
Organized AeroInfluencer properties.
Fix controls when not using flight assist.
Made control system extendable.
Set default throttle to 1 in demo_plane.tscn.
Simplified calculation of angular velocity.
Fix incorrect default bindings in AeroControlComponent.
Change how forces are applied in AeroThrusterComponent to ensure torque is applied properly.
Change default bindings for demo_plane to inclune throttle controls.
Change default drag at mach curve.

Full Changelog: v0.5.1...v0.6.0