Fixed Windows slashes problem.

AUTHORS.txt

@@ -39,6 +39,7 @@ Reinoud Elhorst (@reinhrst)
 Guido van Rossum (@gvanrossum) <guido@python.org>
 Dmytro Sadovnychyi (@sadovnychyi) <jedi@dmit.ro>
 Cristi Burcă (@scribu)
+bstaint (@bstaint)
 
 
 Note: (@user) means a github user name.

jedi/evaluate/compiled/__init__.py

@@ -339,7 +339,11 @@ def dotted_from_fs_path(fs_path, sys_path):
     for s in sys_path:
         if (fs_path.startswith(s) and len(path) < len(s)):
             path = s
-    return _path_re.sub('', fs_path[len(path):].lstrip(os.path.sep)).replace(os.path.sep, '.')
+
+    # - Window
+    # X:\path\to\lib-dynload/datetime.pyd => datetime
+    module_path = fs_path[len(path):].lstrip(os.path.sep).lstrip('/')
+    return _path_re.sub('', module_path).replace(os.path.sep, '.')
 
 
 def load_module(evaluator, path=None, name=None):

test/test_windows.py

@@ -0,0 +1,8 @@
+import jedi
+
+def test_path_issues():
+    """
+    See pull request #684 for details.
+    """
+    source = '''from datetime import '''
+    assert jedi.Script(source).completions()