SIM-hierarchy. It contains all general model definition methods (input-
file parsing, property setup, initial conditions, adaptive refinement).
Changed: Renamed the virtual createModelGenerator to getModelGenerator
plus some cosmetics in console feedback during default model generation.
The latter will require updates of the apps relying on model generators
and regression tests because of cosmetic correction of console feedback.
ModelGenerator sub-classes. Instead, the createG2 method is made virtual.
Also let the createTopology method have an empty default implementation such
that it does not need to be overridden in the single-patch default generators.
And please don't use the override keyword (at least not in the IFEM kernel)
which is not supported i gcc 4.6. I still use that compiler for debugging.
