Make biped file work with Blender 2.80 collections

- Import collection rather than group.
- Changed the blenrig_biped.blend file so that it has nested collections,
  rather than setting layers after importing it.

blenrig_biped/ops_blenrig_biped_add.py

@@ -20,27 +20,11 @@ class Operator_BlenRig5_Add_Biped(bpy.types.Operator):
 
         # Link the top-level collection into the file.
         with bpy.data.libraries.load(filepath, link=False) as (data_from, data_to):
-            data_to.collections = ["BlenRig_Master_Collection"]
-
-        hide_collections = ['Mesh_Deform_Cage', 'Lattices', 'Proxy_Model', 'Bone_Shapes']
+            data_to.collections = ["blenrig_biped"]
 
         # Add the collection(s) to the scene.
         for collection in data_to.collections:
             scene.collection.children.link(collection)
-        for coll in collection.children:
-            if coll.name in hide_collections:
-                coll.hide_viewport = True
-                #Context Override 
-                #areas  = [area for area in bpy.context.screen.areas if area.type == 'OUTLINER']
-
-                #if areas:
-                    #regions = [region for region in areas[0].regions if region.type == 'VIEW_3D']
-
-                    #if regions:
-                        #override = {'area': areas[0],
-                                    #'region': regions[0]}       
-                #bpy.context.view_layer.active_layer_collection = context.view_layer.layer_collection.children[coll.name]
-                #bpy.ops.outliner.show_one_level(open=False)
 
     def execute(self, context):
         self.import_blenrig_biped(context)