- implementing changes to be able to have expressions associated with Dimensions that can be used to caculate the default value of the dimension. it must be an expression because it may involve other previous dimensions in the calculations.
Merge branch 'master' of https://github.com/CaKlassen/DogSweater into Eric
- finished implementing the feature where Dimension instances can have an expression used to calculate its default value (defaultValueExpression).
    - Dimension instances from a Dimensions instance can use the expression to compute their default value
        - this is necessary because other Dimension values may be involved in the calculations