*vangenuchten, box jacobian assembler, box local jacobian, box local residual: various changes

- box jacobian assembler: Do no longer use the PDELab grid operator space to assemble the jacobian.
- vangenuchten: fix typos to make it compile again
- box local jacobian: evaluate local residual inside local jacobian to increase efficiency slightly
- box local residual: correct comment about fluxes

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@4693 2fb0f335-1f38-0410-981e-8018bf24f1b0