Roll Observatory packages and add a roll script

charted/lib/svg/shapes.dart

-//
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
-//
-
-library charted.svg.shapes;
-
-import "dart:html" show Element;
-import "dart:math" as math;
-
-import "package:charted/core/utils.dart";
-import "package:charted/core/interpolators.dart";
-import "package:charted/selection/selection.dart";
-
-part 'shapes/arc.dart';
-part 'shapes/line.dart';
-part 'shapes/area.dart';
-part 'shapes/rect.dart';
-
-/// Common interface provided by all shape implementations.
-abstract class SvgShape {
-  /// Generate the path based on the passed data [d], element index [i]
-  /// and the element [e].  This method follows the same signature as the
-  /// other callbacks used by selection API - [ChartedCallback<String>]
-  String path(d, int i, Element e);
-}