Add ability to handle pathlib paths

- Handle pathlib paths across all implementations, plat_other already did
- Move preprocessing code to common location

send2trash/plat_win_legacy.py

@@ -7,6 +7,8 @@
 from __future__ import unicode_literals
 import os.path as op
 from .compat import text_type
+from .util import preprocess_paths
+
 from ctypes import (
     windll,
     Structure,
@@ -101,8 +103,7 @@ def get_short_path_name(long_name):
 
 
 def send2trash(paths):
-    if not isinstance(paths, list):
-        paths = [paths]
+    paths = preprocess_paths(paths)
     # convert data type
     paths = [
         text_type(path, "mbcs") if not isinstance(path, text_type) else path