Add a base class for commands that provides wad and map arguments.

dcc/doom_base.py

@@ -0,0 +1,8 @@
+from cliff.command import Command
+
+class WadMap(Command):
+	def get_parser(self, prog_name):
+		parser = super().get_parser(prog_name)
+		parser.add_argument('wad')
+		parser.add_argument('map')
+		return parser