* disabled nonsense-copy constructor (using default one instead as before)

1. added viscosisty in \Deta u terms
2. local matrices not transposed

thanks to the 1 vs 0 indexing

fixed compilation with g++ 4.x (this-> issue)

seems like this code was _never_ used

the this-> issue again

treat the existance of a limited number of internal faces in the mesh

Added RegionMesh3D<>:: method  to extract selected goemetrical entities

treat the existance of a limited number of internal faces in the mesh

now it compiles fine and it is somewhat cleaner.