F/app serializers

[justinyost]

Adds an AppSerializer class and documentation regarding the use of it.

Note there are no breaking changes in this PR, however the documentation is updated to reflect that AppSerializer class will probably be the primary base Serializer object developers will build upon.
Closes #53

[justinyost]

Assigning to @beporter for review and feedback.

[beporter]

One specific thing comes to mind:

Does this work even if the consuming Cake project does not have a /Serializer/AppSerializer.php file defined? I'm thinking of how Cake controller's can extend AppController without there actually needing to be a /Controller/AppController.php file in your project.

It seems like the App class needs to know about Plugin/Serializers/Serializer/ as a load path for Serializer objects. All a /Serializer/SomethingSerializer.php file should need to do is App::uses('AppSerializer', 'Serializer'); and have it work whether or not /Serializer/AppSerializer.php exists by falling back to Plugin/Serializers/Serializer/AppSerializer.php.

In other words: It should work exactly like AppController and AppModel.

[justinyost]

@beporter Throwing back for re-review.

[beporter]

Nice work, this looks like it mirrors the behavior of Cake's core classes (Models, Controllers, Components, etc.) when it comes to using a core AppWhatever when one is not present in the app.

👍

[justinyost]

Need to run through this PR and verify it internally before merging.