removing Web UI tutorials, updating remaining 4 to current release, + review pass

src/diagrams/tutorials/polymer-intro/connections.graffle

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
         <key>ActiveLayerIndex</key>
         <integer>0</integer>
         <key>ApplicationVersion</key>
         <array>
                 <string>com.omnigroup.OmniGrafflePro</string>
                 <string>139.18.0.187838</string>
@@ skipping 340 matching lines @@
     &lt;tute-stopwatch&gt;&lt;/tute-stopwatch&gt;\
     \
   &lt;/body&gt;\
 &lt;/html&gt;}</string>
                         </dict>
                         <key>Wrap</key>
                         <string>NO</string>
                 </dict>
                 <dict>
                         <key>Bounds</key>
-                        <string>{{368, 322.99999809265137}, {291, 192}}</string>
+                        <string>{{368, 322.99999809265137}, {327, 164}}</string>
                         <key>Class</key>
                         <string>ShapedGraphic</string>
                         <key>FitText</key>
                         <string>YES</string>
                         <key>Flow</key>
                         <string>Resize</string>
                         <key>ID</key>
                         <integer>3</integer>
                         <key>Shape</key>
                         <string>Rectangle</string>
@@ skipping 24 matching lines @@
 \cocoascreenfonts1{\fonttbl\f0\fmodern\fcharset0 CourierNewPSMT;}
 {\colortbl;\red255\green255\blue255;}
 \deftab720
 \pard\pardeftab720
 
 \f0\fs24 \cf0 import 'dart:html';\
 import 'dart:async';\
 import 'package:polymer/polymer.dart';\
 \
 @CustomTag('tute-stopwatch')\
-class TuteStopwatch\
-        extends PolymerElement\
-        with ObservableMixin \{\
+class TuteStopwatch extends PolymerElement \{\
 \
   @observable String counter = '00:00';\
   \
   ...\
 \}}</string>
                         </dict>
                         <key>Wrap</key>
                         <string>NO</string>
                 </dict>
                 <dict>
@@ skipping 374 matching lines @@
                         <string>LineGraphic</string>
                         <key>Head</key>
                         <dict>
                                 <key>ID</key>
                                 <integer>34182</integer>
                         </dict>
                         <key>ID</key>
                         <integer>34198</integer>
                         <key>Points</key>
                         <array>
-                                <string>{442.18428659425587, 303}</string>
-                                <string>{512.87957873232358, 230}</string>
+                                <string>{442.18396224896401, 303}</string>
+                                <string>{512.87688666640133, 230}</string>
                         </array>
                         <key>Style</key>
                         <dict>
                                 <key>stroke</key>
                                 <dict>
                                         <key>Color</key>
                                         <dict>
                                                 <key>b</key>
                                                 <string>0.909179</string>
                                                 <key>g</key>
@@ skipping 368 matching lines @@
                 <key>twopiSeparation</key>
                 <real>0.0</real>
         </dict>
         <key>LinksVisible</key>
         <string>NO</string>
         <key>MagnetsVisible</key>
         <string>NO</string>
         <key>MasterSheets</key>
         <array/>
         <key>ModificationDate</key>
-        <string>2013-09-30 20:06:03 +0000</string>
+        <string>2013-10-09 23:39:41 +0000</string>
         <key>Modifier</key>
         <string>Mary Campione</string>
         <key>NotesVisible</key>
         <string>NO</string>
         <key>Orientation</key>
         <integer>2</integer>
         <key>OriginVisible</key>
         <string>NO</string>
         <key>PageBreaks</key>
         <string>YES</string>
@@ skipping 88 matching lines @@
                 <array>
                         <array>
                                 <string>Canvas 1</string>
                                 <real>1</real>
                                 <real>1</real>
                         </array>
                 </array>
         </dict>
 </dict>
 </plist>