update default config

- actually define default labels
- document ITEMS
- add pickle to containers

sloth/conf/default_config.py

@@ -1,9 +1,15 @@
 LABELS = (
+    ('Rect',  {'type': 'rect'}),
+    ('Point', {'type': 'point'}),
 )
 
 HOTKEYS = (
 )
 
+# Defines the mapping from the annotation type to the visualization item. The
+# values need to be either python callables, or a module path string that
+# points to a python callable. The callable is responsible for creating and
+# returning the corresponding visualization item.
 ITEMS = {
     'rect':  'sloth.items.RectItem',
     'point': 'sloth.items.PointItem',
@@ -15,8 +21,9 @@ INSERTERS = {
 }
 
 CONTAINERS = (
-    ('*.json', 'sloth.annotations.container.JSONContainer'),
-    ('*.yaml', 'sloth.annotations.container.YAMLContainer'),
+    ('*.json',   'sloth.annotations.container.JSONContainer'),
+    ('*.yaml',   'sloth.annotations.container.YAMLContainer'),
+    ('*.pickle', 'sloth.annotations.container.PickleContainer'),
 )
 
 PLUGINS = (