Add option to change shutdown/reboot keys (#487)

Include options in the configuration to change which function keys to use for shutdown and reboot.
Fix config.map_len size in src/config.c.
Add missing defaults in config_defaults() in src/config.c.

res/lang/tr.ini

@@ -34,12 +34,12 @@ err_user_init = kullanici oturumu baslatilamadi
 err_user_uid = kullanici icin UID ayarlanamadi
 err_xsessions_dir = oturumlar klasoru bulunamadi
 err_xsessions_open = oturumlar klasoru acilamadi
-f1 = F1 makineyi kapat
-f2 = F2 yeniden baslat
 login = kullanici
 logout = oturumdan cikis yapildi
 numlock = numlock
 password = sifre
+restart = yeniden baslat
 shell = shell
+shutdown = makineyi kapat
 wayland = wayland
 xinitrc = xinitrc