Moved core files from libs directory to src

src/core/music/ttuneobject.cpp

src/core/music/ttuneobject.h

src/core/nootkaconfig.h

src/core/nootkacoreglobal.h

src/core/picts

src/core/qtr.h

src/core/score/taddnoteitem.cpp

src/core/score/taddnoteitem.h

src/core/score/tbeamobject.cpp

src/core/score/tbeamobject.h

src/core/score/tdummychord.cpp

src/core/score/tdummychord.h

src/core/score/tmeasureobject.cpp

src/core/score/tmeasureobject.h

src/core/score/tmelodypreview.cpp

src/core/score/tmelodypreview.h

src/core/score/tnoteitem.cpp

src/core/score/tnoteitem.h

src/core/score/tnotepair.cpp

src/core/score/tnotepair.h