Do not skip NodeElems with constrained DoFs!
Do not skip NodeElems with constrained DoFs!

I know Akselos uses NodeElems for some sort of trickery, so we won't
risk breaking that by trying to assemble on a NodeElem, but I'm trying
to use NodeElems in IGA meshes for entirely *different* trickery, for
which we do need to apply Dirichlet constraints (when they exist, which
is common) on a NodeElem.

dschwen/libmesh,BalticPinguin/libmesh,BalticPinguin/libmesh,dschwen/libmesh,libMesh/libmesh,dschwen/libmesh,dschwen/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,dschwen/libmesh,dschwen/libmesh,libMesh/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,libMesh/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,dschwen/libmesh,dschwen/libmesh,libMesh/libmesh,libMesh/libmesh,libMesh/libmesh,BalticPinguin/libmesh,libMesh/libmesh,BalticPinguin/libmesh,libMesh/libmesh