Update Redirecting section in Routing guide

 * The `redirect` hook is now deprecated in favor of `beforeModel` and `afterModel`.
Custom JSON Transforms : Update sample code

The 'registerTransform' method has been removed, and there is a new
way to register a custom JSON transform.
Add back and bring up-to-date filtering section in Redirecting guide
Add section headers to Redirecting guide
adding BrandingBrand to users
Update the transform example to match the latest changes.
using public api for queries, instead of private store.findQuery
Explain 'App' and how it relates to Ember and fix line length
Remove redundant word.
Improve observers guide
Use `action` instead of `event`.

Resolves #919.
Update links.md to display Handlebars code snippet correctly on website

Adds an extra line to allow website to display Handlebars code snippet correctly.
Wrapped body with has a x-handlebars template.

The TodoMVC tutorial wasn't working after step "displaying-model-data" because the http://emberjs.com/guides/getting-started/creating-a-static-mockup/ step didn't include this from the start. It is in the Live Preview but this might confuse beginners.
Note that the redirect hook can be used the same as afterModel can
Move Object Model section closer to beginning of guides
Use mapBy and findBy instead of mapProperty and findProperty

Removes the deprecated mapProperty and findProperty references
in the documentation.
capitalize the letter
Add a recipe for using modal dialogs
Add Using Modal Dialogs to guides.yml
Add shell syntax highlighting to README