Add TextStyle fontFamily:, extend support for fontWeight:

sky/examples/rendering/render_paragraph.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:sky';
 import 'package:sky/app/view.dart';
+import 'package:sky/painting/text_style.dart';
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/object.dart';
 import 'package:sky/rendering/flex.dart';
 import 'package:sky/rendering/paragraph.dart';
 import '../lib/solid_color_box.dart';
 
 AppView app;
 
 void main() {
   RenderFlex flexRoot = new RenderFlex(direction: FlexDirection.vertical);
@@ skipping 19 matching lines @@
       [new InlineText(meatyString)]);
   child = new RenderDecoratedBox(
     decoration: new BoxDecoration(backgroundColor: const Color(0xFFFFFFFF)),
     child: new RenderParagraph(text)
   );
   flexRoot.add(child);
   child.parentData.flex = 1;
 
   app = new AppView(root: root);
 }