Initial import of SRB stuff from the scf_shirley repository.

The SRB related files were pulled in using:
  git checkout scf_shirley/master <filename>
A few names were changed, most notably
s/shirley/srb and s/compact/reduced

This commit passes the standard ref/srb tests
for all.set with 1 or 2 cores.

The main changes to the 'normal' QE come in:
 * run_pwscf
 * electrons_scf
 * stres_knl
 * init_run
 * setup
 * read_namelists
 * read_cards
 * input_parameters

A few rountines were given more explicit interfaces:
 * gen_us_dj
 * gen_us_dy
 * weights
 * addusdens_g

A few inputs were added:
 * Q_POINTS card
 * srb namelist

The only change a use_srb = .false. run should see
is a bands.dat file output when calc = nscf

Known issues:
 * Forces haven't been brought in yet
 * The issue with Efermi for semi-metals is still here;  will
   be resolved with a merge in from maxhutch