Work on allowing TimeSignatures to be edited.

It is safe to compile and run this,
but the option in question is a no-op for now.

Themes/_fallback/Languages/en.ini

@@ -831,6 +831,7 @@ Edit steps information=Edit steps information
 Exit Edit Mode=Exit Edit Mode
 Edit stop=Edit stop
 Edit delay=Edit delay
+Edit time signature=Edit time signature (not working yet)
 Editor options=Options
 EditorShowBGChangesPlay=Show Backgrounds
 Effect=Effect

src/ScreenEdit.cpp

@@ -507,6 +507,7 @@ static MenuDef g_MainMenu(
 	MenuRowDef( ScreenEdit::edit_bpm,			"Edit BPM change",		true, EditMode_Full, true, true, 0, NULL ),
 	MenuRowDef( ScreenEdit::edit_stop,			"Edit stop",			true, EditMode_Full, true, true, 0, NULL ),
 	MenuRowDef( ScreenEdit::edit_delay,			"Edit delay",			true, EditMode_Full, true, true, 0, NULL ),
+	MenuRowDef( ScreenEdit::edit_time_signature,		"Edit time signature",		true, EditMode_Full, true, true, 0, NULL ),
 	MenuRowDef( ScreenEdit::play_preview_music,		"Play preview music",		true, EditMode_Full, true, true, 0, NULL ),
 	MenuRowDef( ScreenEdit::exit,				"Exit Edit Mode",		true, EditMode_Practice, true, true, 0, NULL )
 );
@@ -3093,6 +3094,9 @@ void ScreenEdit::HandleMainMenuChoice( MainMenuChoice c, const vector<int> &iAns
 				10
 				);
 			break;
+		case edit_time_signature:
+			// TODO: Actually implement this.
+			break;
 		case play_preview_music:
 			PlayPreviewMusic();
 			break;

src/ScreenEdit.h

@@ -313,6 +313,7 @@ public:
 		edit_bpm,
 		edit_stop,
 		edit_delay,
+		edit_time_signature,
 		play_preview_music,
 		exit,
 		save_on_exit,