Revision 1704

Branch commit:

DataTagged::addTag() = Add a tag with default value. (All uses that I can find 
apart from test code only require this anyway).

DataAbstract now knows its own shape, rank and number of values and have accessors 
for them.
Data Objects also have acessors for these but query their DataAbstracts for the 
answers.

Data::getDataAtOffset() = access to a particular point in the underlying array. (At 
the moment this call references the DataArrayView, but that will change when I have 
everything else working).

DataTagged::getDataByTag() = same but search by tag.
DataTagged::getDefaultValue() = returns default value without obvious reference to 
DataArrayView


C_GeneralTensorProduct_J  is my temporary copy of C_GeneralTensorProduct for 
experimentation.
It and a number of other temporary functions live in JoelMods.cpp_ for now.