Fix bug caused by change in collections.UserList.

- Collections.UserList changed betweeen python 3.7.3 and 3.7.5,
  requiring the constructor of Entry to be a like that for a list.
- Solved by not using UserList and defining __getitem__ and __len__.

TODO

@@ -264,7 +264,6 @@ Ideas
 - Let the mouse click on the actions in the status bar?
 - Let the mouse click the filenames.  Try to show a result from the same type
   of tool.
-- Check if class Entry is really working correctly as a collections.UserList.
 - Docstrings
 - Add ESC as an alternative to 'q' for quit. If looking at Help, ESC should just
   exit the help screen.
@@ -439,3 +438,5 @@ Shelved
   - Not necessary since git_diff was removed.
 - Cache tools._python_version.
   - Not supporting python2 anymore.
+- Check if class Entry is really working correctly as a collections.UserList.
+  - Entry is no longer a UserList.

eris/__main__.py

@@ -80,15 +80,14 @@ KEYS_DOC = """Keys:
 """
 
 
-class Entry(collections.UserList):
+class Entry:
 
     def __init__(self, path, results, summary, highlighted=None,
                  set_results=True):
-        collections.UserList.__init__(self, results)
         self.path = path
         self.summary = summary
         self.highlighted = highlighted
-        self.widgets = self.data
+        self.widgets = results
         if set_results:
             # FIX: this is missed for entries appended later
             for result in results:
@@ -96,6 +95,12 @@ class Entry(collections.UserList):
         self.widget = fill3.Row(results)
         self.appearance_cache = None
 
+    def __len__(self):
+        return len(self.widgets)
+
+    def __getitem__(self, index):
+        return self.widgets.__getitem__(index)
+
     def _get_cursor(self):
         result_selected = self.widget[self.highlighted]
         status_color = tools._STATUS_COLORS.get(