Move cursor to the origin on DECSET 1049, like Terminal and Konsole to make...

Move cursor to the origin on DECSET 1049, like Terminal and Konsole to make less output look nicer. Issue 3408.

sources/VT100Terminal.m

@@ -593,6 +593,7 @@ static const int kMaxScreenRows = 4096;
                         [self saveCursor];
                         [delegate_ terminalShowAltBuffer];
                         [delegate_ terminalClearScreen];
+                        [delegate_ terminalMoveCursorToX:1 y:1];
                     } else {
                         [delegate_ terminalShowPrimaryBuffer];
                         [self restoreCursor];