Rewritten dcd.cfg.Config

Config now supports full hierarchical and overlay-capable usage.
A generic tree overlay function is in aux.

dcd/aux.py

@@ -77,3 +77,32 @@ def hex_to_raw(text, separator=" "):
 	return bytearray(output)
 
 # ----------------------------------------------------------------
+
+class DeleteOverlay:
+	pass
+
+def overlay_tree(base, overlay):
+	"""
+	For every key path in `overlay`, sets the leaf value of the same
+	key path in `base`. Any missing non-leaf keys will be created.
+	
+	To delete a key, set its overlay value to DeleteOverlay.
+	"""
+	
+	stack = [(base, overlay)]
+	
+	while stack:
+		base_p, over_p = stack.pop()
+		
+		for k, v in over_p.items():
+			if v is DeleteOverlay:
+				del base_p[k]
+			else:
+				if type(v) is dict:
+					if k not in base_p or type(base_p[k]) is not dict:
+						base_p[k] = {}
+					
+					stack.append((base_p[k], over_p[k]))
+				
+				else:
+					base_p[k] = v