added DG Qk space (using equidistant Lagrange)
evaluate boundary condition in each Gauss point.
Prevents assertion to be thrown for nonuniform, computed
flow fields.
QkDG basis with Gauss Lobatto points added
evaluate degree 0 polynomials at the center!
Merge branch 'develop_fastDG'

Conflicts:
	dune/pdelab/boilerplate/pdelab.hh