WIP: new project variable to store the PTM mode

src/CMakeLists.txt

src/core/identificationgroup.cpp

src/core/identificationgroup.h

src/core/project.cpp

src/core/project.h

src/grouping/ptm/ptmgroupingexperiment.cpp

src/grouping/ptm/ptmgroupingexperiment.h

src/grouping/ptm/ptminterface.cpp

src/grouping/ptm/ptminterface.h

src/grouping/ptm/ptmmethylation.cpp

src/grouping/ptm/ptmmethylation.h

src/grouping/ptm/ptmphospho.cpp

src/grouping/ptm/ptmphospho.h

src/gui/project_view/projectwindow.cpp

src/gui/project_view/projectwindow.h

src/gui/workerthread.cpp

src/gui/workerthread.h

src/input/xtpxpipsaxhandler.cpp

src/main.cpp

src/output/xpip.cpp