AdaptInfo: test-cout added (could be deleted)
ConditionalEstimator: should run over all elements, but there's an error (adapts only one times)

Implement element dof iterator class. May be used to iterate over all dofs of one element independent of dimension and degree of basis functions.

Added files for InteriorBoundary, a class that defines a boundary within the domain. This is used for domain decomposition parallelization.