Added several more HTML5 samples

src/site/samples/appcache/example/appcache.mf

Index: src/site/samples/appcache/example/appcache.mf
diff --git a/src/site/samples/appcache/example/appcache.mf b/src/site/samples/appcache/example/appcache.mf
new file mode 100644
index 0000000000000000000000000000000000000000..8934cad1857e18dacaa202a1958895e8ee051ecb
--- /dev/null
+++ b/src/site/samples/appcache/example/appcache.mf
@@ -0,0 +1,20 @@
+CACHE MANIFEST
+# Adding a version number and/or timestamp here is a good strategy. Changing
+# the manifest file, even a comment line, will force the browser to refresh its
+# cached resources.
+# 2012-09-28:v2
+
+# Explicitly cached entries. This should be enough to run the sample.
+CACHE:
+index.html
+appcache.css
+appcache.dart
+http://dart.googlecode.com/svn/branches/bleeding_edge/dart/client/dart.js
+
+# All other resources (e.g. sites) require the user to be online.
+NETWORK:
+*
+
+# offline.html will be displayed if the user is offline.
+FALLBACK:
+/ offline.html