Ticket #4107: bind ctrl-i to the ChangePanel action.

After ef5f1fa3eb02e628fce3c26afe2f85eb36191834 ctrl-i stopped working
on some terminals including native Linux console.

To fix this, add default binging ctrl-i shortcut to ChangePanel action.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

misc/mc.default.keymap

@@ -1,5 +1,5 @@
 [main]
-ChangePanel = tab
+ChangePanel = tab; ctrl-i
 Help = f1
 UserMenu = f2
 View = f3

misc/mc.emacs.keymap

@@ -1,5 +1,5 @@
 [main]
-ChangePanel = tab
+ChangePanel = tab; ctrl-i
 Help = f1
 UserMenu = f2
 View = f3

src/keybind-defaults.c

@@ -90,7 +90,7 @@ typedef struct global_keymap_ini_t
 
 /* midnight */
 static const global_keymap_ini_t default_main_keymap[] = {
-    {"ChangePanel", "tab"},
+    {"ChangePanel", "tab; ctrl-i"},
     {"Help", "f1"},
     {"UserMenu", "f2"},
     {"View", "f3"},