open the in-memory output stream immediately when scheduling it on the run loop
- if never opened (as was the case if no response was received) apparently calling close will not implicitly remove the stream from the runloop (apple docs are misleading?)
AFImageCache protocol should inherit from NSObject
fix for import as cocoa touch framework as module to a swift only project

Signed-off-by: Stephan Krusche <krusche@in.tum.de>
Fixes an issue with the request serializer silently handling an error

When a query string serialization block is set on
`AFHTTPRequestSerializer`, if it was to fail with an error it would be
silently handled and the serialization would still return an NSURLRequest.
[Request Serialization] Add `valueForHTTPHeaderField:`

Since we have `setValue:forHTTPHeaderField:` it makes sense to have a
similar method to retrieve them.
Adding test for success block on 204 response
[Issue #2201] Adding @synthesize delegate to AFMultipartBodyStream
Merge branch 'master' of github.com:AFNetworking/AFNetworking
[Issue #2237] Correcting documentation for URLSessionDidFinishEventsForBackgroundURLSession delegate method and reorganizing code accordingly
Merge pull request #2232 from kylef/request-serializer-valueForHTTPHeaderField

[Request Serialization] Add `valueForHTTPHeaderField:`
Minor reformatting
Merge branch 'AFURLRequestSerialization-error' of github.com:kylef/AFNetworking into kylef-AFURLRequestSerialization-error

Conflicts:
	Tests/Tests/AFHTTPRequestSerializationTests.m
Fixing 204 response test
Merge pull request #2206 from krusche/master

fix for import as cocoa touch framework as module to a swift only project
Merge pull request #2179 from marcelofabri/patch-1

AFImageCache protocol should inherit from NSObject
[Issue #2239] Adding [manager.reachabilityManager startMonitoring] to README
Merge branch 'master' of github.com:AFNetworking/AFNetworking
Fixing merge from 61b7a9babab736fc05fc11fb2d2b57e58be982c9
[Issue #2156] Fixing issue caused by passing nil as destination in download task method
Squashed commit of the following:

commit ae493edadcce0b3dd7d0c737ef1611a9c5c313f6
Author: Mattt Thompson <m@mattt.me>
Date:   Tue Aug 12 12:29:47 2014 -0700

    Renaming AFNetworkingOperationFailingURLResponseOriginalDataErrorKey to AFNetworkingOperationFailingURLResponseDataErrorKey

commit 09cf2f758748fe753757af25b9185eb552419708
Merge: efaa26d 66c0736
Author: Mattt Thompson <m@mattt.me>
Date:   Tue Aug 12 12:29:02 2014 -0700

    Merge branch 'getOriginalData' of github.com:yageek/AFNetworking into yageek-getOriginalData

commit 66c07365ad82663e28c76b6cefb15adf6cac2ddb
Author: Yannick Heinrich <yannick.heinrich@gmail.com>
Date:   Thu Jul 24 16:08:29 2014 +0200

    Retrieve data on response deserialisation error

    Add new constant
    `AFNetworkingOperationFailingURLResponseOriginalDataErrorKey` to
    retrieve the original data from the request when the response is
    considered  invalid