added .cmake export file for (sub)library generation (usefull for external NICE usage via cmake

cmake/NiceModules.cmake

@@ -125,7 +125,8 @@ macro(nice_build_library)
   TARGET_LINK_LIBRARIES("nice_${the_library}" ${nice_${the_library}_LINKING_DEPENDENCIES})
   #TARGET_LINK_LIBRARIES("nice_${the_library}" ${nice_${the_library}_LINKING_DEPENDENCIES} ${Boost_LIBRARIES} ${OPENGL_LIBRARY} ${GLUT_LIBRARY} ${QT_LIBRARIES})
   SET_PROPERTY(TARGET "nice_${the_library}" PROPERTY FOLDER "library")
-  INSTALL(TARGETS "nice_${the_library}" DESTINATION lib)
+  INSTALL(TARGETS "nice_${the_library}" DESTINATION lib EXPORT "nice_${the_library}-exports")
+  INSTALL(EXPORT "nice_${the_library}-exports" DESTINATION lib/exports)
 
   configure_file( ../cmake/niceConfig.cmake.in "${PROJECT_BINARY_DIR}/lib/nice_${the_library}Config.cmake" )
 endmacro()