Implemented configurable serializers.

Signed-off-by: Jason Lewis <jason.lewis1991@gmail.com>
Fixed conflict in tests/TransformerAbstractTest.php
Formatting and alpha ordered some methods.
Added extra test to see if collections nest their data before serialization properly.
Fixes #29: Added Infinite embed protection.
By default you cannot include items more than 10 levels deep. It just wont show up. I imagine this might cause some HUH moments for some, but its better than letting folks spam the shit out of your server with really long request strings.
Merge included data with data when serializer does not want sideloaded data.

Signed-off-by: Jason Lewis <jason.lewis1991@gmail.com>