remove trailing white spaces from iterator.hh

additionally the codim number is still unique but will not overflow ever

Also, enable HSFC for 2d grids.

We want to sort after correcting the element orientation,
because in the 2-3 grid the convention is, that it is oriented by
the orientation of the first inserted element.

added dimension == 2 to if-clause for recreateboundaryids as it basically reorientates the boundaroies

for some reason you cannot use 999 as bounadryid for hte fake boundaries, because then the linkage breaks