Implement fully undo/redo with checks

While these actions are short in the backend--taking about 0.01 seconds to run--the Blender UI lags a lot leading to 2-3 second pauses because of the "refresh_brick_viewer" function being slow. This should be investigated.

src/blenderbim/blenderbim/bim/module/brick/operator.py

@@ -190,6 +190,20 @@ class RemoveBrick(bpy.types.Operator, Operator):
             brick_uri=props.bricks[props.active_brick_index].uri,
         )
 
+class UndoBrick(bpy.types.Operator, Operator):
+    bl_idname = "bim.undo_brick"
+    bl_label = "Undo Brick"
+
+    def _execute(self, context):
+        core.undo_brick(tool.Brick)
+
+class RedoBrick(bpy.types.Operator, Operator):
+    bl_idname = "bim.redo_brick"
+    bl_label = "Redo Brick"
+
+    def _execute(self, context):
+        core.redo_brick(tool.Brick)
+
 class SerializeBrick(bpy.types.Operator, Operator):
     bl_idname = "bim.serialize_brick"
     bl_label = "Serialize Brick"