SMM12 — Allow more flexibility in defining a RescaledMeasure.

Some rescalings are not strictly linear transformations, but also require a single non-linear operation. For example, the rule of 72 is a common rule of thumb to calculate how long it takes before an investment doubles in value: #years = 72/Interest Rate. This is a rescaling from interest rate to years.
SMM could directly support such rescaling by removing the constraint which requires that either the operation property is empty or the multiplier/offset properties are empty. SMM would need to indicate whether the operation is applied first or the multiplier and offset are applied first. A new Boolean property, operationFirst, would suffice. Its default can be false. With that this new property has a default value, it is better to then also defined defaults for the existing properties. So, SMM should also specify the defaults multiplier = 1 and offset = 0.
The rule of 72 would then be a rescaling with multiplier 72, offset 0, operation "reciprocal", and operationFirst set.
This will also generally improve the expressiveness of a RescaledMeasure.

Introduce operationFirst Boolean

Enable that, for a Rescaled Measure, operation, offset and multiplier can be applied in combination, whereby it can also be specified in which order they are applied. Next to this, default values are specified for the attributes.