Show current status to stderr

Every time it starts working with a new catalyst (i.e. moving on to the next catalyst as the "first catalyst to react with the reaction") It prints out the message to the console.

ptbsearch2.c

@@ -47,6 +47,8 @@ int iperturb, thisgen;
 
    for (iperturb=0; iperturb<nperturbs; iperturb++) {
 
+     if(depth == 0) fprintf(stderr, "Working with perturber #%d\n", iperturb+1);
+
      copyLifeList(seed, reaction+depth);
      setValues(reaction[depth].cellList, reaction[depth].ncells, 1);