Hidden directory not skipped when at top level
When building a local library with `mopidy local scan`, hidden directories are being skipped, but only if they are in a subdirectory of the `media_dir`. If they are directly in the `media_dir`, they are scanned.

I believe the offending code is in class `ScanCommand#121`, which checks for `/.` in the relative path.

diff --git a/mopidy/local/commands.py b/mopidy/local/commands.py
index ead874a0..862d1d0b 100644
--- a/mopidy/local/commands.py
+++ b/mopidy/local/commands.py
@@ -118,7 +118,7 @@ class ScanCommand(commands.Command):
             relpath = os.path.relpath(abspath, media_dir)
             uri = translator.path_to_local_track_uri(relpath)
 
-            if b'/.' in relpath:
+            if b'/.' in relpath or relpath.startswith(b'.'):
                 logger.debug('Skipped %s: Hidden directory/file.', uri)
             elif relpath.lower().endswith(excluded_file_extensions):
                 logger.debug('Skipped %s: File extension excluded.', uri)
['mopidy/local/commands.py']