add Electrum to browser build and tests

browser/build.js

@@ -30,6 +30,7 @@ var modules = [
   'lib/Bloom',
   'lib/Connection',
   'lib/Deserialize',
+  'lib/Electrum',
   'lib/Message',
   'lib/Opcode',
   'lib/Peer',

test/index.html

@@ -22,6 +22,7 @@
     <script src="test.Bloom.js"></script>
     <script src="test.Connection.js"></script>
     <script src="test.EncodedData.js"></script>
+    <script src="test.Electrum.js"></script>
     <script src="test.Key.js"></script>
     <script src="test.main.js"></script>
     <script src="test.Message.js"></script>