Added dumpdir definition to file_admin: directory where iteration
dump files will be placed.
Synchronized with the mpi.F90 and no_mpi.F90 in C2Ray_3Dm1D_He.
Disabled calcualting (and overwriting) the electron density inside
doric. It is not clear how to properly handle this but for now it
seems better not to have the recalculation of the electron density
as a side efffect of doric.
Some minor changes triggered by synchronizing with evolve8.F90
from C2Ray_3Dm1D_He

- Added local_chemistry logical to test whether we ran do_chemistry
  with the local option on (in evolve0d). In that case the ionization fractions
  where changed and need to be communicated in case of an MPI run.
- Added dump_dir as directory where iteration dump files should go.
- Added heating and temperature grid to variables to be dumped; preparation
  for non-isothermal runs.
- Introduced variable total_source_flux to check for photon losses.
  This makes it equivalent to the C2Ray_3Dm1D_He version.
Change in initialization of ionization fractions. According to RECFAST
the mean ionization state at z=30 is about 2e-4. This is now used
to initialize the fractions.
Added the ALLFRAC preprocessor option to the version of material.

We can either work only with the ionized fraction (standard) or
both with ionized and neutral fractions (use -DALLFRAC at compile time).
Merge branch 'master' of github.com:garrelt/C2-Ray3Dm