Compile AFNetworking for iOS 6 and iOS 7

- By using __IPHONE_OS_VERSION_MAX_ALLOWED and
  __MAC_OS_X_VERSION_MAX_ALLOWED, it will allow users who have minimum
  of iOS 6 or Mac OSX 10.8 to levarage NSURLSession for users on iOS 7
  and Mac OSX 10.9
Compile AFNetworking for iOS 6 and iOS 7

- By using __IPHONE_OS_VERSION_MAX_ALLOWED and
  __MAC_OS_X_VERSION_MAX_ALLOWED, it will allow users who have minimum
  of iOS 6 or Mac OSX 10.8 to levarage NSURLSession for users on iOS 7
  and Mac OSX 10.9
Update README.md

NSSearchPathForDirectoriesInDomains returns an array of NSString.
The NSString has to be converted to NSURL.
Merge pull request #1413 from l4u/patch-2

Update README.md
Fix up format

Remove leftover portion of error message, where format string uses
an argument that no longer is passed, causing the error message to
have a random number added to it:

	Request failed: %@ (%d), got %d

The ", got %d" portion is a left-over from a previous iteration of
the message, and the value it expects is now the one provided in
the parentesis before it.
Change `AFHTTPRequestOperation` `-(id)initWithCoder:` to call the `super` implementation

This change allows an instance of AFHTTPRequestOperation to be more completely archived.
Update UIProgressView+AFNetworking.m

Hi there,
Thanks for the awesome job!!
Just found a tiny bug. I think in Line 174, the selector should be "countOfBytesReceived".
Cheers and have a nice weekend!!

Allen
Remove the unused protection space block type

Related to #1441
Remove the lock podfile

It doesn't matter what version pods are for testing, this isn't a production
app. It's more cumbersome to ensure the lockfile is in-sync than the benefits
it's worth.
Don't test on iOS 5. AFNetworking doesn't even support iOS 5
Add image response serializer to UIButton+AFNetworking.
Without this fix, the responseObject is nil and the image does not get updated.
Merge pull request #1446 from kylef/ios5

Don't test on iOS 5. AFNetworking doesn't even support iOS 5
Merge pull request #1443 from kylef/cleanup-unused

Remove the unused protection space block type
Merge pull request #1442 from musicchamber/patch-1

Update UIProgressView+AFNetworking.m
[Issue #1438] nil -> NULL for better clarity on unused out parameter
Merge pull request #1435 from joshavant/master

Change `AFHTTPRequestOperation -(id)initWithCoder:` to call the `super` implementation
Merge pull request #1433 from tholo/format-fix

Fix up format
Ensure only ASCII is used in the User-Agent header.

The charset for HTTP headers has to be ASCII at best
and is ill defined at worst.

My Applikation has a Bundle Name with Umlauts in it
which results in bessy Webserver log files due to the
"strange" engoding of the App name.
To me it seems, that AFNetworking is meant to transcode the
App name to ASCII but the implementation is lacking and thus
only encodes to Latin1/ISO8859-1.
This patch - although not tested with Asian scripts - should
result in User-Agent strings always beeing ASCII while remaining
mostly unchanged.

So `Überland/0.16.27` becomes `Uberland/0.16.27` which is much
more standards compliant.
Merge branch 'master' of github.com:AFNetworking/AFNetworking
CFSTR -> __bridge CFStringRef