cleanup finiteelementmaps
Goals:
- Seperate files for finiteelements and finiteelementmaps.
- Move finiteelements to dune/pdelab/finitelement/.
- Adjust header guards.
- Remove some unused code (some CG stuff in qkdg).
- We now have several versions of QkDG: lagrange, lobatto, legendre and opb. The lagrange, lobatto and legendre versions have all the same signature. Have one file dune/pdelab/finitelement/qkdg.hh and one class QkDGLocalFiniteElementMap with the possibility to switch between lagrange, lobatto and legendre and opb. Finite elements will move to dune/pdelab/finitelement/.
Replace typedefs with using in moved files and do some cleanup since history is lost anyway.