Update RealSolarSystem.cs
useLegacyAtmosphere fixed

Removed accidental resetting of useLegacyAtmosphere = true
pressureCurve data + useLegacyAtmosphere

added pressureCurve data and useLegacyAtmosphere = false. RealSolarSystem can now use pressureCurve data to replace the outdated bugged atmosphere model.
Update RealSolarSystem.cfg
Merge pull request #2 from Starwaster/master

pressureCurve implementation