Add Environmental Reference type for Temperature and Pressure References

[sequc82]

The issue first presented itself in #422 where a reference pressure was needed to convert gauge, absolute and vacuum pressures. It was resolved in #422 with a public property ReferencePressure.AtmosphericPressure. It has come up again in #724 when discussing another wrapper type ReferenceVolumeFlow, but in this case both the atmospheric Temperature and Pressure.

Create an EnvironmentalReference type, which would be accessible at a level similar to UnitSystem.

For Example:

public enum StandardReference
{
    StandardUS,
    StandardISO,
    StandardAGA,
    Normal,
    Custom
}

public struct EnvironmentalReference
{
	public EnvironmentalReference(Pressure p, Temperature t, double RelativeHumidity)
    {
		/*Assign properties here*/
    }
	
	public static Dictionary<StandardReference, EnvironmentalReference> StandardReferences { get; } = new Dictionary<StandardReference, EnvironmentalReference>()
        {
            {StandardReference.StandardUS, new EnvironmentalReference(Pressure.FromPoundsForcePerSquareInch(14.696), Temperature.FromDegreesFahrenheit(60), 0)},
			/*Define subsequent StandardReferences here*/
        };
{

I'm still trying to understand the usage and storage of UnitSystem, but I would think EnvironmentalReferencewould be similar toUnitSystem, with the STP conditions being similar to BaseUnits, and the DictionaryofStandardReferencewould be similar toUnitSystem.SIif it stored a collection ofUnitSystem` instead of only SI.

[angularsen]

Please see some background on UnitSystem. It was an experimental feature in v4 that we later found to have design flaws for basically any other unit system than SI, so we have some ideas on how to change that for v5.

#630 (PR trying to map CGS and FPS unit systems, failed)
#651
#666
#709 (PR trying to repurpose UnitSystem)

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.