change solvers, utilities, etc. to use while (..) time-looping idiom

- this (now deprecated) idiom:
      for (runTime++; !runTime.end(); runTime++) { ... }
  has a few problems:
    * stop-on-next-write will be off-by-one (ie, doesn't work)
    * function objects are not executed on exit with runTime.end()
  Fixing these problems is not really possible.

- this idiom
      while (runTime.run())
      {
          runTime++;
          ...
      }
  works without the above problems.

tutorials/MRFSimpleFoam/MRFSimpleFoam/MRFSimpleFoam.C

@@ -52,8 +52,9 @@ int main(int argc, char *argv[])
 
     Info<< "\nStarting time loop\n" << endl;
 
-    for (runTime++; !runTime.end(); runTime++)
+    while (runTime.run())
     {
+        runTime++;
         Info<< "Time = " << runTime.timeName() << nl << endl;
 
 #       include "readSIMPLEControls.H"

tutorials/simpleSRFFoam/simpleSRFFoam/simpleSRFFoam.C

@@ -54,8 +54,9 @@ int main(int argc, char *argv[])
 
     Info<< "\nStarting time loop\n" << endl;
 
-    for (runTime++; !runTime.end(); runTime++)
+    while (runTime.run())
     {
+        runTime++;
         Info<< "Time = " << runTime.timeName() << nl << endl;
 
 #       include "readSIMPLEControls.H"