Modified Array Class tutorial, added examples

doc/examples/Tutorial_ArrayClass_addition.cpp

@@ -0,0 +1,22 @@
+#include <Eigen/Dense>
+#include <iostream>
+
+using namespace Eigen;
+using namespace std;
+
+int main()
+{
+  ArrayXXf a(3,3);
+  ArrayXXf b(3,3);
+  
+  a << 1,2,3,
+       4,5,6,
+       7,8,9;
+
+  b << 1,2,3,
+       1,2,3,
+       1,2,3;
+       
+  cout << "a + b = " << endl
+       << a + b << endl;
+}