document the fixture adapter for ember data

Added some documentation on usage of the Fixture Adapter with an example
of subclassing DS.Model.
Added line about the active class getting added to links
Update source/guides/models/the-fixture-adapter.md

Fixed FixtureStore example to be more consistent with Ember's naming conventions.
Fix for #291

Fix for #291
Merge pull request #292 from darthdeus/patch-2

Fix for #291
Fix typo
Add NoSoloSoftware to who's using
Implicit route not being created when resource is not given a function
Fixed some CSS

* Bug with underlining buttons
* background color in code snippets
Merge pull request #296 from wifelette/master

Fixed some homepage CSS
Merge pull request #293 from KidkArolis/patch-1

Fix typo
Fixed underlining in footer links, added opacity
Merge pull request #298 from wifelette/footer-links

Fixed underlining in footer links, added opacity
Add {{else}} documentation for {{each}} helper

The `{{else}}` documentation was missing for the `{{each}}` helper.
A PR is made on emberjs/emberjs#1966. 
I just added the example in the Templates guide.
Merge pull request #299 from lcoq/patch-1

Add {{else}} documentation for {{each}} helper in Templates guide
Merge pull request #295 from joeytrapp/no-implicit-index

Implicit route not being created when resource is not given a function
Merge pull request #294 from javierav/master

Add NoSoloSoftware to who's using
Update class and instance documentation

- Clarify new create/extend semantics around
overriding methods/computed properties
- Document `init` method (closes #289)
Added new User page, tweaked carousel
Removed unnecessary styling