guessing windows needed include vector

Former-commit-id: 0f560524f9c7f15edfc6710b4f87325dfcd4709a

tutorial/706_FacetOrientation/main.cpp

@@ -9,6 +9,8 @@
 #include <fstream>
 #include <iostream>
 #include <string>
+#include <vector>
+
 igl::viewer::Viewer viewer;
 Eigen::MatrixXd V;
 std::vector<Eigen::VectorXi> C(2);