Proportional editing support for the action editor.

There are a few things here which are not so nice:

* Position of proportional edit circle is not centered on data
(difficult to predict positions here since those are completely custom,
 will probably be positioned at center of area later instead)

* Result is flushed to curve handles only at the end of the transform,
so if people have the graph editor open they will see handles lagging behind.

release/scripts/startup/bl_ui/space_dopesheet.py

@@ -105,6 +105,7 @@ class DOPESHEET_HT_header(Header):
         layout = self.layout
 
         st = context.space_data
+        toolsettings = context.tool_settings
 
         row = layout.row(align=True)
         row.template_header()
@@ -133,6 +134,11 @@ class DOPESHEET_HT_header(Header):
             # filters which will work here and are useful (especially for character animation)
             dopesheet_filter(layout, context, genericFiltersOnly=True)
 
+        row = layout.row(align=True)
+        row.prop(toolsettings, "proportional_edit", icon_only=True)
+        if toolsettings.proportional_edit != 'DISABLED':
+            row.prop(toolsettings, "proportional_edit_falloff", icon_only=True)
+
         # Grease Pencil mode doesn't need snapping, as it's frame-aligned only
         if st.mode != 'GPENCIL':
             layout.prop(st, "auto_snap", text="")