Added a 'pretty printer' for the msvc debugger (tested on Visual Studio 2008).
Added a 'pretty printer' for the msvc debugger (tested on Visual Studio 2008).

rotorliu/eigen,mjbshaw/Eigen,rotorliu/eigen,rotorliu/eigen,madlib/eigen_backup,mjbshaw/Eigen,madlib/eigen_backup,mjbshaw/Eigen,madlib/eigen_backup,madlib/eigen_backup,mjbshaw/Eigen,rotorliu/eigen