[tests] used fused gtest source instead of shipping entire archive

dune/stuff/test/CMakeLists.txt

 enable_testing()
 
 set_source_files_properties( ${DUNE_HEADERS} PROPERTIES HEADER_FILE_ONLY 1 )
-add_subdirectory(gtest)
-include_sys_dir(${CMAKE_CURRENT_SOURCE_DIR}/gtest/include )
+include_dir(${CMAKE_CURRENT_SOURCE_DIR} )
 
 file( GLOB test_sources "${CMAKE_CURRENT_SOURCE_DIR}/*.cc" )
 
 foreach( source ${test_sources} )
 	get_filename_component(testname ${source} NAME_WE)
-	add_executable( ${testname} ${source} ${DUNE_HEADERS} )
+	add_executable( ${testname} ${source} ${DUNE_HEADERS} ${CMAKE_CURRENT_SOURCE_DIR}/gtest/gtest-all.cc)
 	add_test( ${testname} ${CMAKE_CURRENT_BINARY_DIR}/${testname} )
-	target_link_libraries( ${testname} boost_filesystem boost_system boost_timer boost_thread ${DUNE_LIBS} gtest )
-	LIST(APPEND testnames ${testname} )
+	target_link_libraries( ${testname} boost_filesystem boost_system boost_timer boost_thread ${DUNE_LIBS} )
+	list(APPEND testnames ${testname} )
 endforeach( source )
 
 #grid pgf output