Added /clear command to clear current window

src/ui/ui.h

@@ -99,6 +99,7 @@ void title_bar_draw(void);
 
 // current window actions
 void win_current_close(void);
+void win_current_clear(void);
 int win_current_is_console(void);
 int win_current_is_chat(void);
 int win_current_is_groupchat(void);

src/ui/windows.c

@@ -550,6 +550,13 @@ ui_switch_win(const int i)
     dirty = TRUE;
 }
 
+void
+win_current_clear(void)
+{
+    wclear(current->win);
+    dirty = TRUE;
+}
+
 void
 win_current_close(void)
 {