Fix for NSProgress bug where two child NSProgress instances are added to a parent NSProgress.
AFURLSessionManagerTaskDelegate creates a NSProgress in its initializer. However, -[AFURLSessionManager addDelegateForUploadTask:progress:completionHandler:] assigns a new NSProgress to the delegates progress property.
When using -[NSProgress becomeCurrentWithPendingUnitCount:] two NSProgress children are added, as two are created in the current parent's context.
Fix iOS test app detail text label.
Fix file names in file comment.
Merge pull request #2453 from tewha/header

Fix old file names in file header comments.
Merge pull request #2451 from shepting/master

Fix iOS Example App Detail Label
Minor refactoring
Merge pull request #2445 from mediumbear/master

Fix for NSProgress bug where two child NSProgress instances are added to...
Use builtin __Require macros from AssertMacros.h

The `AF_Require` and `AF_Require_noErr` macros were introduced in de8b20f for solving #2015. It turns out there exist exactly equivalent macros in the AssertMacros.h header, respectively `__Require_Quiet` and `__Require_noErr_Quiet`.
Merge pull request #2462 from 0xced/require-from-assertmacros

Use builtin __Require macros from AssertMacros.h