[4.1] HttpClients rework

[yguedidi]

For me, it doesn't make sense to technically be possible to call getResponseHeaders() or getResponseHttpStatusCode() before a call to send(). (because they're public)
I propose to only have a send() method in FacebookHttpClientInterface that take headers in arguments (something like @SammyK did in #169) but instead returns the raw body, returns an array with the raw body, the status code and response header, because theses data are linked together.
This will also ease tests of the coming FacebookClient :)

@gfosco, @SammyK any thoughts ?

[SammyK]

Makes sense to me. If #169 gets pulled it this could be a nice update.

[gfosco]

Sure.

[SammyK]

I also like how you sent in the FacebookRequest entity as the only argument in send().

[yguedidi]

I'll work on it as soon as possible ;)

[SammyK]

Hey @yguedidi! All this stuff has been reworked so I think we can close this one too?

[yguedidi]

Yes!