jsonp support

[arnold-almeida]

I have got a temporary implementation for jsonp support.

Personally, i think it should fallback to a standard json response if the "callback" parameter is not supplied

https://gist.github.com/arnold-almeida/2f656202153b3e161bcb

If thats cool ill submit a PR.

[jasonlewis]

It probably wouldn't be bad but my only gripe is using $_GET in there. I'm just looking at it now, the only other way would be to inject the current request into each response formatter in the service provider. You can send a PR. You'll probably have to make the ResponseFormatInterface an abstract class called ResponseFormat so that it can have a setRequest method or something.

[arnold-almeida]

Yeah totally agree, ill see what i can do over the weekend.

[jasonlewis]

No worries, cheers @arnold-almeida.

[jasonlewis]

Continued in #35.