Add .perpendicular() function in Geometry module (adapted from Eigen1)
Documentation:
* add an overview for each module.
* add an example for .all() and Cwise::operator<
diff --git a/doc/snippets/MatrixBase_all.cpp b/doc/snippets/MatrixBase_all.cpp
new file mode 100644
index 0000000..4a39e21
--- /dev/null
+++ b/doc/snippets/MatrixBase_all.cpp
@@ -0,0 +1,7 @@
+Vector3f boxMin(Vector3f::Zero()), boxMax(Vector3f::Ones());
+Vector3f p0 = Vector3f::Random(), p1 = Vector3f::Random().cwise().abs();
+// let's check if p0 and p1 are inside the axis aligned box defined by the corners boxMin,boxMax:
+cout << "Is (" << p0.transpose() << ") inside the box: "
+ << ((boxMin.cwise()<p0).all() && (boxMax.cwise()>p0).all()) << endl;
+cout << "Is (" << p1.transpose() << ") inside the box: "
+ << ((boxMin.cwise()<p1).all() && (boxMax.cwise()>p1).all()) << endl;