[URL Operation] Use the ivar directly in initialization

This is to prevent calling the custom setter inside initialization which
broadcasts KVO notifications and relies on existing state which isn't
yet setup.

Re #1845
[URL Operation] Don't allow transitioning to invalid states
Use "long long" instead of "NSInteger" on byte count.

Byte count should always be 64bit integer. Otherwise, AFNetworking won't work on streams
larger than 4GB in 32bits mode. This commit revert the PR #1772 and e94a52c.
Added test to check content type
Explicitly importing MobileCoreServices.
Fixes failing test
Update license year

Fix outdated copyright year (updated to 2014).
The copyright year was out of date. Copyright notices must reflect the current year, so this commit updates the listed year to 2014.

See http://www.copyright.gov/circs/circ01.pdf for more info.
care for 'Content-Length'  on taskDidSendBodyData block
Update README to use SVG for Travis Icon [ci skip]
Merge pull request #1958 from MaxGabriel/patch-1

Update README to use SVG for Travis Icon
Use SecTrust return status code at runtime

The `SecTrust` functions in use within AFSecurityPolicy.h only make use of the return code when `NS_BLOCK_ASSERTIONS` is not defined. The use of NS_BLOCK_ASSERTIONS to silence static analyzer warnings about unused values is convenient, however the larger issue is the failure of `AFPublicKeyForCertificate`, `AFPublicKeyTrustChainForServerTrust` and `AFServerTrustIsValid` to detect a runtime status code that is not `errSecSuccess` and to return early.
-scale has existed since iOS 4.0. No need to check for it.
Update README.md

Gives deprecated warning without error parameter
Merge pull request #1972 from petard/patch-1

Update README.md
[Issue #1974] Deprecating setAuthorizationHeaderFieldWithToken:
Merge branch 'master' of github.com:AFNetworking/AFNetworking
Merge pull request #1966 from sgoodwin/master

-scale has existed since iOS 4.0. No need to check for it.
Update example to use NSFileManager -URLForDirectory:...
Adding removesKeysWithNullValues property to AFJSONResponseSerializer
Merge branch 'master' of github.com:AFNetworking/AFNetworking
[Issue #1799] Implement respondsToSelector for NSURLSession delegate methods to conditionally respond to optional selectors if and only if a custom block has been set