feat(editor): Signals mode of the Tracks window (H): semaphores, block, warning, shunting, stop, substitute signals and repeaters placed by the track from the templates of the scenery, described by //$e signal: (kind, mount, lamps, lean, the event the train reads them by) which tools/editor/signal_headers.py writes into them; a click by a track puts the signal on that side 2.25 m from the axis at the rail heads, facing the trains which have it on their right, a drag along turns it to the trains going the way of the drag; its (p1)_sem_info goes to event1 or event2 of the path, warning signals and repeaters, which the train doesn't read, get none; a head leaning away from the track swapped for its counterpart; the plate named like the signal; signals dragged along the track with their event, removed with it, renamed in the node properties with it, each a single step of the undo history; Polish translation

CMakeLists.txt

@@ -195,6 +195,7 @@ set(SOURCES
 "application/editormodeparallel.cpp"
 "application/editormodelineside.cpp"
 "application/editormodevehicle.cpp"
+"application/editormodesignal.cpp"
 "application/editormodesweep.cpp"
 "application/editormodeturntable.cpp"
 "application/editormodeselftest.cpp"