Use path.anchor instead of path.root for Windows compatibility

On *nix they give the same output, but on Windows path.anchor includes
'C:', which is needed for path.relative to work.

Author: johnomotani

xbout/load.py

@@ -539,7 +539,7 @@ def _expand_wildcards(path):
     """Return list of filepaths matching wildcard"""
 
     # Find first parent directory which does not contain a wildcard
-    base_dir = Path(path.root)
+    base_dir = Path(path.anchor)
 
     # Find path relative to parent
     search_pattern = str(path.relative_to(base_dir))