Clean unit tests compilation.

CMakeLists.txt

tests/CMakeLists.txt

tests/test_depend.cpp

tests/test_pool.cpp

tests/test_signalcast.cpp

tests/test_signalcast_libA.cpp

tests/test_signalcast_libA.h

tests/test_signalcast_libB.cpp

tests/test_signalcast_libB.h