Access rules directories in sorted order

This provides a stable rule parsing order. e.g.
A directoory named `10-overrides` will always be accessed after
`00-default`, rather than in the order the filesystem returns.

Closes #274

ananicy.py

@@ -506,7 +506,7 @@ def dir_must_exits(self, path):
 
     def find_files(self, path, name_mask):
         files = []
-        entries = os.listdir(path)
+        entries = sorted(os.listdir(path))
         if not entries:
             return files
         for entry_name in entries: