refactoring, adding add existing file menu
refactoring, adding add existing file menu

tagspaces/tagspaces,cbop-dev/tagspaces,tagspaces/tagspaces,tagspaces/tagspaces,tagspaces/tagspaces,tagspaces/tagspaces,tagspaces/tagspaces,tagspaces/tagspaces,cbop-dev/tagspaces,tagspaces/tagspaces,cbop-dev/tagspaces