UseOrocos: adding pkg-config path for catkin workspaces which have yet to be source'd
useorocos: renamed OROCOS_DEFINED_TARGETS to ${PROJECT_NAME}_EXPORTED_TARGETS because this nicely integrates with catkin. Added ${PROJECT_NAME}_EXPORTED_INCLUDE_DIRS for typekits.

Signed-off-by: Johannes Meyer <johannes@intermodalics.eu>