* lib/cm.h (cm_timer_t): Add fields to handle wallclock time.
  (cm_timer_wc_get): Declare new function.
* lib/timer.c (cm_timer_wc_get): New function.
  (cm_timer_start): Rewrite to avoid code duplication with...
  (cm_timer_reset, cm_timer_continue): ...these. Also handle wallclock time.
  (cm_timer_stop): Also handle wallclock time.
* lib/cm-impl.h (cm_mpi_get_tonelli): Change prototype to return CPU time.
* lib/mpi.c (cm_mpi_get_tonelli): Implement return value.
  (mpi_worker): Measure and send CPU time over MPI.
* lib/ecpp.c (compute_qstar): Change prototype to take a stat argument.
  In the MPI case, track CPU time separately of the global timer.
  (find_ecpp_discriminant): Adapt function call, drop handling of time,
  print wallclock time for the qstar.
  (cm_ecpp): Print wallclock time.