Changed the gdb display format of vectors and added support for quaternions.
Changed the gdb display format of vectors and added support for quaternions.

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