Get Market Spot Value

Function Get Market Spot Value within
Quotable returns the default spot value under which the supplied quotable is supposedly quoted, before it is overriden by any user-supplied market data.
If a real time data provider exists, then this will be just the quote delivered by that provider.
On the absence of such a provider, a fixed value is returned, which is not the result of a calculation.
Note this value is used in the initial construction by Deriscope of relevant default market data.