Big improvements for the custom elements system, some other changes.
* People can now use the content inside each custom element (<wcontent>)
* Add tagname attribute to <welement>, the custom element registration is changed
, now only one call is needed for a whole custom element file
* Can now perform initialization via the method Init of custom element model
to make custom behaviors for custom elements
* Recognize true/false in the bind string syntax
* Add len() helper
Merge branch 'master' of github.com:phaikawl/wade
forgot to reenable the uncommented for testing part in app.go

Conflicts:
	testapp/TodoMVC/app.go
Update README.md
Update README.md
Make a <switchmenu> for the menu, and improve the binding system to
accommodate it.
Merge branch 'master' of github.com:phaikawl/wade
huge change, revamped page system, remove <wpage>, use an attribute instead
Adjust the http service to have the same blocking API as go's standard http
Add js dependency check. Remove ordered binding because HTML attributes
order is different among browsers. Implement the real functionality of
<wrapper>, it's now stripped from display.