Excessive warnings printing from all MPI tasks

[conradtchan]

#258 reduced some of the duplicated output lines due to MPI.

#268 clobbered some of these improvements so the output is noisy again. This is a real nuisance when running with a large number of MPI tasks.

The simple fix is to change in eos.F90:1216:

if (id==master) write(iprint,*) 'qfacdisc = ',qfacdisc

and eos.F90:1228:

if (id==master) write(iprint,*) 'qfacdisc2 = ',qfacdisc2

Additionally, as a separate problem, there are "errors" raised in the extract calls in read_headeropts_eos when quantities cannot be found, e.g.

 ERROR: could not find dtmax0 in header

which are repeated across all MPI tasks. These errors do not cause the code to halt because ierr is ignored and changed back to zero in eos.F90:1210:

 ierr = 0

The following needs to be resolved:

• Change output so that it only prints on master
• Determine if the errors should actually just be warnings
• Make the error/warning printout more concise so that the output log is readable