use while (runTime.loop() { .. } where possible in solvers

- change system/controlDict to use functions {..} instead of functions (..);
  * This is internally more efficient
- fixed formatting of system/controlDict functions entry

- pedantic change: use 'return 0' instead of 'return(0)' in the applications,
  since return is a C/C++ keyword, not a function.

applications/test/tensor/tensorTest.C

@@ -65,5 +65,5 @@ int main()
     Info<< (symm(t7) && t7) - (0.5*(t7 + t7.T()) && t7) << endl;
     Info<< (t7 && symm(t7)) - (t7 && 0.5*(t7 + t7.T())) << endl;
 
-    return(0);
+    return 0;
 }