Allow ceres to be used with the latest version of Eigen

Change-Id: Ief3b0f6b405484ec04ecd9ab6a1e1e5409a594c2

include/ceres/jet.h

diff --git a/include/ceres/jet.h b/include/ceres/jet.h
index fc98d44..5b6c0ca 100644
--- a/include/ceres/jet.h
+++ b/include/ceres/jet.h
@@ -811,6 +811,7 @@
   typedef ceres::Jet<T, N> Real;
   typedef ceres::Jet<T, N> NonInteger;
   typedef ceres::Jet<T, N> Nested;
+  typedef ceres::Jet<T, N> Literal;
 
   static typename ceres::Jet<T, N> dummy_precision() {
     return ceres::Jet<T, N>(1e-12);
@@ -831,6 +832,14 @@
     HasFloatingPoint = 1,
     RequireInitialization = 1
   };
+
+  template<bool Vectorized>
+  struct Div {
+    enum {
+      AVX = false,
+      Cost = 1
+    };
+  };
 };
 
 }  // namespace Eigen