Changed Wind Indicator UI

Wind speed text is properly hidden when GUI is hidden.

New feature: Wind now controls wind turbine power output. No longer is wind a reliable energy source on planets with atmosphere.

Wind turbine output is determined by the level of impedance along the wind direction only. Please also be warned you should orient wind turbines vertically for maximum output.

Turbines will produce their maximum output in 6m/s wind.

New planetary defaults for wind (will not be set in old saves, but you can manually fix it)
Max speed 20m/s
Wind change rate 3600

Wind is now more horizontal to the ground.

Wind speed has more variation in velocity.

Known issue: Mod cannot control the spin rate of the turbine yet.

Performance improvements.