[SWP-24] Added a MetaTreeItem to change the cancel distance in the menu.
[SWP-24] Added a MetaTreeItem to change the cancel distance in the menu.

mne-tools/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,LorenzE/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,LorenzE/mne-cpp,LorenzE/mne-cpp,ViktorKL/mne-cpp,mne-tools/mne-cpp,chdinh/mne-cpp,chdinh/mne-cpp,mne-tools/mne-cpp,LorenzE/mne-cpp,chdinh/mne-cpp,ViktorKL/mne-cpp