Display MainGame.mnu and map in ordoor simultaneously

It's a complete mess for now - many things are out of place or shown
when they shouldn't be - and we can't move around the game map. But,
it's a good start.

internal/flow/main_game.go

@@ -0,0 +1,55 @@
+package flow
+
+// TODO: There are Chaos and Ultramarine versions of MainGame. Do we really want
+// to duplicate everything for both?
+
+func (f *Flow) linkMainGame() {
+	// 3: Action menu
+
+	// 4: Interface options menu
+	f.onClick(mainGame, "4.1", f.setReturningDriver(mainGame, options)) // Options button
+	// 4.2: Map button
+	// 4.3: Mission objectives button
+	// 4.4: Inventory
+	// 4.5: Next man
+	// 4.6: Next enemy
+	// 4.7: Total enemy text
+
+	// 5:  Holding menu
+	// 6:  View menu
+	// 7:  General character menu
+	// 8:  Character stats
+	// 9:  Visible enemy menu
+	// 10: Friendly squad menu
+	// 11: Psyker spell dialogue
+
+	// FIXME: lots and lots and lots of wiring up to do.
+	// For now, just link all the exit buttons to go back to the bridge
+	f.onClick(mainGame, "11.6", func() {
+		f.scenario = nil
+		f.returnToLastDriverNow(mainGame)
+	})
+
+	// 12: Inventory dialogue
+	f.onClick(mainGame, "12.21", func() {
+		f.scenario = nil
+		f.returnToLastDriverNow(mainGame)
+	})
+
+	// 13: Exchange menu
+
+	f.onClick(mainGame, "13.1", func() {
+		f.scenario = nil
+		f.returnToLastDriverNow(mainGame)
+	})
+
+	// 14: Map
+
+	// 15: Interface wing left
+	// 16: Interface wing right
+	// 17: Grenade dialogue
+	// 18: Info dialogue
+	// 19: Turn start dialogue
+	// 20: Chat menu
+	// 21: Chat list menu box
+}