Cleanup: Split effect.h, rename opc_client

examples/cpp/dot.cpp

examples/cpp/lib/effect.h

examples/cpp/lib/effect_mixer.h

examples/cpp/lib/effect_runner.h

examples/cpp/lib/opc_client.h

examples/cpp/mixer.cpp

examples/cpp/particle_trail.cpp

examples/cpp/rings.cpp

examples/cpp/simple.cpp

examples/cpp/spokes.cpp