Allow user to enter arbitrary strings for NECI input files
Allow user to enter arbitrary strings for NECI input files

The user can now add as many extra options as they want to
system, calc and logging blocks of the NECI input file.
Also, the symmetry in the 'sym' option can be input by the user.

gkc1000/pyscf,sunqm/pyscf,sunqm/pyscf,gkc1000/pyscf,gkc1000/pyscf,sunqm/pyscf,gkc1000/pyscf,gkc1000/pyscf,sunqm/pyscf