Fix common grid

This closes the issue that devel did not compile with enabled lhapdf but disabled applgrid. It turned out to be a bit more deeper issue, related to the CommonGrid.cc code, which should in principle work without applgrid, but it did not. Now the code is adjusted such that CommonGrid.cc, TheorEval.cc and ftheor_eval_dum.cc are linked for all configurations. The fix is by using APPLGRID_ENABLE based conditional compilation, this was started by Andrey it seems but was not finalized. Some standard header files were included which were missing before. The side benefit of the fix, that now FastNLO theory expression interface works without need to enable applgrid.