Beginnings of Retro Mode

This just adds a GUI/command line option to set the variable into world for retro mode and puts the universal key item into the list of defined items. None of the functionality is yet present.

EntranceRandomizer.py

@@ -165,6 +165,10 @@ def start():
                              Keys (and other dungeon items) are no longer restricted to
                              their dungeons, but can be anywhere
                              ''', action='store_true')
+    parser.add_argument('--retro', help='''\
+                             Keys are universal, shooting arrows costs rupees,
+                             and a few other little things make this more like Zelda-1.
+                             ''', action='store_true')
     parser.add_argument('--custom', default=False, help='Not supported.')
     parser.add_argument('--customitemarray', default=False, help='Not supported.')
     parser.add_argument('--nodungeonitems', help='''\