Move source files to src subdirectory

agui2/CMakeLists.txt

agui2/src/Converter.cpp

agui2/src/Converter.hpp

agui2/src/Graphics/Connection/Connection.cpp

agui2/src/Graphics/Connection/Connection.hpp

agui2/src/Graphics/Connection/ConnectionBox.cpp

agui2/src/Graphics/Connection/ConnectionBox.hpp

agui2/src/Graphics/Connection/InputConnectionBox.cpp

agui2/src/Graphics/Connection/InputConnectionBox.hpp

agui2/src/Graphics/Connection/OutputConnectionBox.cpp

agui2/src/Graphics/Connection/OutputConnectionBox.hpp

agui2/src/Graphics/Dialogs/InputDialog.cpp

agui2/src/Graphics/Dialogs/InputDialog.hpp

agui2/src/Graphics/Dialogs/InputDialog.ui

agui2/src/Graphics/Dialogs/OutputDialog.cpp

agui2/src/Graphics/Dialogs/OutputDialog.hpp

agui2/src/Graphics/Dialogs/OutputDialog.ui

agui2/src/Graphics/Dialogs/ResultDialog.cpp

agui2/src/Graphics/Dialogs/ResultDialog.hpp

agui2/src/Graphics/Dialogs/ResultDialog.ui