Various documentation updates:
- update the tutorial
- update doc of deprecated cwise function
- update cwise doc snippets
diff --git a/doc/snippets/MatrixBase_array.cpp b/doc/snippets/MatrixBase_array.cpp
new file mode 100644
index 0000000..f215086
--- /dev/null
+++ b/doc/snippets/MatrixBase_array.cpp
@@ -0,0 +1,4 @@
+Vector3d v(1,2,3);
+v.array() += 3;
+v.array() -= 2;
+cout << v << endl;