* rework Map, allow vectorization

* rework PacketMath and DummyPacketMath, make these actual template
specializations instead of just overriding by non-template inline
functions
* introduce ei_ploadt and ei_pstoret, make use of them in Map and Matrix
* remove Matrix::map() methods, use Map constructors instead.

Eigen/src/Core/util/Meta.h

@@ -147,6 +147,13 @@ template<typename T> struct ei_packet_traits
   enum {size=1};
 };
 
+template<typename T> struct ei_unpacket_traits
+{
+  typedef T type;
+  enum {size=1};
+};
+
+
 template<typename Scalar, int Rows, int Cols, int MaxRows, int MaxCols, unsigned int SuggestedFlags>
 class ei_corrected_matrix_flags
 {