Ticket #1655: Unable to call 'direct' viewer (by shift+f3) key.

Test case:
Try to press shift+F3.
 * Old behavior: call viewer in raw mode.
 * New behavior: do nothing.

Fix issue:
For 'PanelViewSimple' event changed hotkey from 'shift-F3' to 'F13'

Signed-off-by: Slava Zanko <slavazanko@gmail.com>

misc/mc.keymap

@@ -215,7 +215,7 @@ PanelNextPage = pgdn; ctrl-v
 PanelDoEnter = enter
 PanelChdirOtherPanel = alt-o
 PanelChdirToReadlink = alt-l
-PanelViewSimple = shift-F3
+PanelViewSimple = F13
 PanelEditNew = F14
 PanelCopyLocal = F15
 PanelRenameLocal = F16