cmake tf2_eigen examples

LimHyungTae/patchwork CMakeLists.txt :23 

find_package(tf2_eigen REQUIRED)

stella-cv/stella_vslam_ros CMakeLists.txt :126 

find_package(tf2_eigen REQUIRED)

septentrio-gnss/septentrio_gnss_driver CMakeLists.txt :161 

find_package(tf2_eigen REQUIRED)