allow better performance for repeated invocations of find_in_workspaces()
allow better performance for repeated invocations of find_in_workspaces()

asmodehn/catkin,wkentaro/catkin,harmishhk/catkin,scpeters/catkin,thaddeustaylor/catkin,ros/catkin,shyamalschandra/catkin,shyamalschandra/catkin,beni55/catkin,asmodehn/catkin,jack-oquin/catkin,harmishhk/catkin,harmishhk/catkin,shyamalschandra/catkin,thaddeustaylor/catkin,scpeters/catkin,jack-oquin/catkin,ros/catkin,thaddeustaylor/catkin,ros/catkin,beni55/catkin,asmodehn/catkin,beni55/catkin,wkentaro/catkin,wkentaro/catkin,jack-oquin/catkin,scpeters/catkin