Further changes related to the introduction of DOF weights.
Added a missing "this->".
Changed a literal from double to int.
Enhancements in the implementation of PiecewiseLinearNormallyContinuousVectorSpace.
Removed unnecessary asserts in array classes.
Added a variant of evaluateAtSpecialPoints() that returns points besides values.
Implemented the surface div functor.
Implemented the single-layer boundary op. for Maxwell equations.