Tests: Update CMake tutorial

Latest material from data.kitware.com -> Collections -> Courses -> CMake.

Tests/Tutorial/Step2/MathFunctions/mysqrt.cxx

@@ -1,5 +1,5 @@
 #include "MathFunctions.h"
-#include <stdio.h>
+#include <iostream>
 
 // a hack square root calculation using simple operations
 double mysqrt(double x)
@@ -8,19 +8,16 @@ double mysqrt(double x)
     return 0;
   }
 
-  double result;
-  double delta;
-  result = x;
+  double result = x;
 
   // do ten iterations
-  int i;
-  for (i = 0; i < 10; ++i) {
+  for (int i = 0; i < 10; ++i) {
     if (result <= 0) {
       result = 0.1;
     }
-    delta = x - (result * result);
+    double delta = x - (result * result);
     result = result + 0.5 * delta / result;
-    fprintf(stdout, "Computing sqrt of %g to be %g\n", x, result);
+    std::cout << "Computing sqrt of " << x << " to be " << result << std::endl;
   }
   return result;
 }