[pitivi] layer: Add pydocs

[Alexandru Băluț <alexbalut src gnome org>]

commit 581294110853438dd35d5f304243cbf9b1efe317
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Tue Aug 30 14:10:50 2016 +0200

    layer: Add pydocs
    
    Differential Revision: https://phabricator.freedesktop.org/D1290

 pitivi/timeline/layer.py |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/timeline/layer.py b/pitivi/timeline/layer.py
index 27bcd73..3595eb6 100644
--- a/pitivi/timeline/layer.py
+++ b/pitivi/timeline/layer.py
@@ -99,6 +99,7 @@ class SpacedSeparator(Gtk.EventBox):
 
 
 class LayerControls(Gtk.EventBox, Loggable):
+    """Container with widgets for controlling a layer."""
 
     __gtype_name__ = 'PitiviLayerControls'
 
@@ -286,7 +287,7 @@ class LayerControls(Gtk.EventBox, Loggable):
 
 
 class LayerLayout(Gtk.Layout, Loggable):
-    """Displays the clips of a layer."""
+    """Container for the clips of a layer."""
 
     __gtype_name__ = "PitiviLayerLayout"
 
@@ -338,6 +339,7 @@ class LayerLayout(Gtk.Layout, Loggable):
 
 
 class Layer(Gtk.EventBox, Zoomable, Loggable):
+    """Container for a layer plus decorations (separators)."""
 
     __gtype_name__ = "PitiviLayer"