Squashed commit of the following:

commit c5463a0dfdf501425354ca02e774c79b809df582
Author: Mattt Thompson <m@mattt.me>
Date:   Thu Jun 5 17:06:54 2014 -0700

    Refactoring configuration of callback queue / group

commit 69d04fe8a44eedfcb0b96cba5931f8599c2c49b5
Merge: f042803 56c2ba1
Author: Mattt Thompson <m@mattt.me>
Date:   Thu Jun 5 17:02:42 2014 -0700

    Merge branch 'master' of github.com:robertmryan/AFNetworking into robertmryan-master

commit 56c2ba124d7d782d145a300bc4a72d20eb9a6c7f
Author: robertmryan <robert.ryan@mindspring.com>
Date:   Sun May 25 09:28:01 2014 -0400

    Correct location of completionQueue/completionGroup properties in header

commit 96ce766fc2687e7c2bfff41e41e2d91b4fee8228
Author: robertmryan <robert.ryan@mindspring.com>
Date:   Sun May 25 09:21:25 2014 -0400

    Add `completionQueue` and `completionGroup` properties to `AFHTTPRequestOperationManager`, which will be supplied to `AFHTTPRequestOperation` objects.