Update beets to 1.3.18:

Dependencies:
* PyYAML 3.11
* Unidecode 0.4.19
* beets 1.3.18
* colorama 0.3.7
* enum34 1.1.6
* jellyfish 0.5.4
* munkres 1.0.7
* musicbrainzngs 0.6
* mutagen 1.32

libs/beets/util/hidden.py

@@ -0,0 +1,88 @@
+# -*- coding: utf-8 -*-
+# This file is part of beets.
+# Copyright 2016, Adrian Sampson.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+
+"""Simple library to work out if a file is hidden on different platforms."""
+from __future__ import division, absolute_import, print_function
+
+import os
+import stat
+import ctypes
+import sys
+
+
+def _is_hidden_osx(path):
+    """Return whether or not a file is hidden on OS X.
+
+    This uses os.lstat to work out if a file has the "hidden" flag.
+    """
+    file_stat = os.lstat(path)
+
+    if hasattr(file_stat, 'st_flags') and hasattr(stat, 'UF_HIDDEN'):
+        return bool(file_stat.st_flags & stat.UF_HIDDEN)
+    else:
+        return False
+
+
+def _is_hidden_win(path):
+    """Return whether or not a file is hidden on Windows.
+
+    This uses GetFileAttributes to work out if a file has the "hidden" flag
+    (FILE_ATTRIBUTE_HIDDEN).
+    """
+    # FILE_ATTRIBUTE_HIDDEN = 2 (0x2) from GetFileAttributes documentation.
+    hidden_mask = 2
+
+    # Retrieve the attributes for the file.
+    attrs = ctypes.windll.kernel32.GetFileAttributesW(path)
+
+    # Ensure we have valid attribues and compare them against the mask.
+    return attrs >= 0 and attrs & hidden_mask
+
+
+def _is_hidden_dot(path):
+    """Return whether or not a file starts with a dot.
+
+    Files starting with a dot are seen as "hidden" files on Unix-based OSes.
+    """
+    return os.path.basename(path).startswith('.')
+
+
+def is_hidden(path):
+    """Return whether or not a file is hidden.
+
+    This method works differently depending on the platform it is called on.
+
+    On OS X, it uses both the result of `is_hidden_osx` and `is_hidden_dot` to
+    work out if a file is hidden.
+
+    On Windows, it uses the result of `is_hidden_win` to work out if a file is
+    hidden.
+
+    On any other operating systems (i.e. Linux), it uses `is_hidden_dot` to
+    work out if a file is hidden.
+    """
+    # Convert the path to unicode if it is not already.
+    if not isinstance(path, unicode):
+        path = path.decode('utf-8')
+
+    # Run platform specific functions depending on the platform
+    if sys.platform == 'darwin':
+        return _is_hidden_osx(path) or _is_hidden_dot(path)
+    elif sys.platform == 'win32':
+        return _is_hidden_win(path)
+    else:
+        return _is_hidden_dot(path)
+
+__all__ = ['is_hidden']