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
Update the transform example to match the latest changes.
using public api for queries, instead of private store.findQuery
Merge pull request #997 from alexspeller/improve-observer-guide

Improve observers guide
Merge pull request #993 from sly7-7/ember-data-queries

Refer to public api for queries instead of private store.findQuery
Merge pull request #760 from jagthedrummer/jeremy/models-transforms

Custom JSON Transforms : Update sample code
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.
Merge pull request #999 from bluk/patch-1

Update links.md to display Handlebars code snippet correctly on website
Merge pull request #1000 from hbarroso/patch-1

Wrapped body with a x-handlebars template.
Merge pull request #998 from rjackson/use_action_in_router_docs

Use `action` instead of `event`.
Note that the redirect hook can be used the same as afterModel can
Move Object Model section closer to beginning of guides
Merge pull request #1002 from alexspeller/change-object-model-position

Move Object Model section closer to beginning of guides
Merge pull request #768 from balinterdi/update-redirecting-guide

Update Redirecting section in Routing guide
Use mapBy and findBy instead of mapProperty and findProperty

Removes the deprecated mapProperty and findProperty references
in the documentation.