Add removesKeysWithNullValues setting to serialization and copying.

Preserve removesKeysWithNullValues through copying and serialization.
CocoaDocs colour scheme

Think this goes pretty well your AFNetworking.com branding. You're welcome to go make your own at http://cocoadocs.org/readme/

![http://cl.ly/image/2Z2c0h390L0M/Screen%20Shot%202014-07-01%20at%2010.20.36%20PM.png](http://cl.ly/image/2Z2c0h390L0M/Screen%20Shot%202014-07-01%20at%2010.20.36%20PM.png)
Merge pull request #2168 from orta/patch-2

CocoaDocs colour scheme
Merge pull request #2162 from jshier/master

Add removesKeysWithNullValues to serialization and copying.
Ensure copyWithZone: calls the parent imp

AFURLConnectionOperation implements NSCopying, so we need to call the
parent's version of copyWithZone: to ensure the object is properly
copied.
Merge pull request #2172 from streeter/copywithzone-in-subclasses

Ensure AFHTTPRequestOperation's copyWithZone: calls the parent implementation
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.
NSSecureCoding

Fix minor typo in which NSecureCoding was referenced in comments and pragmas, and I assume NSSecureCoding was intended.
[Request Serialization] Add `valueForHTTPHeaderField:`

Since we have `setValue:forHTTPHeaderField:` it makes sense to have a
similar method to retrieve them.
Merge pull request #2230 from robertmryan/master

NSSecureCoding
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