Add forgotten documentation for:

orientation(Vector_2, Vector_2)
  orientation(Vector_3, Vector_3, Vector_3)

Kernel_23/doc_tex/Kernel_23_ref/orientation.tex

@@ -10,6 +10,14 @@ line $l$ defined by $p$ and $q$, returns \ccStyle{RIGHT_TURN} if $r$
 lies to the right of $l$, and returns \ccStyle{COLLINEAR} if $r$ lies
 on $l$.}
 
+\ccHtmlNoLinks
+\ccFunction{Orientation orientation(const Vector_2<Kernel>& u,
+                                    const Vector_2<Kernel>& v);}
+{returns \ccStyle{LEFT_TURN} if $u$ and $v$ form a left turn,
+returns \ccStyle{RIGHT_TURN} if $u$ and $v$ form a right turn,
+and returns \ccStyle{COLLINEAR} if $u$ and $v$ are collinear.}
+
+
 \ccHtmlNoLinks
 \ccFunction{Orientation orientation(const Point_3<Kernel> &p,
                                    const Point_3<Kernel>&q,
@@ -20,10 +28,18 @@ plane $h$ defined by $p$, $q$, and $r$, returns \ccStyle{NEGATIVE} if $s$
 lies on the negative side of $h$, and returns \ccStyle{COPLANAR} if $s$ lies
 on $h$.}
 
+\ccHtmlNoLinks
+\ccFunction{Orientation orientation(const Vector_3<Kernel> &u,
+                                    const Vector_3<Kernel> &v,
+                                    const Vector_3<Kernel> &w);}
+{returns \ccStyle{POSITIVE} if $u$, $v$ and $w$ are positively oriented,
+returns \ccStyle{NEGATIVE} if $u$, $v$ and $w$ are negatively oriented,
+and returns \ccStyle{COPLANAR} if $u$, $v$ and $w$ are coplanar.}
+
+
 \ccSeeAlso
 \ccRefIdfierPage{CGAL::collinear}\\
 \ccRefIdfierPage{CGAL::left_turn}\\
 \ccRefIdfierPage{CGAL::right_turn}
 
 \end{ccRefFunction}
-