Added return status checks when building list of pinned public keys
Added return status checks when handling connection's authentication challenge
Fix bug where examples always used AFSSLPinningModeNone
Remove all _AFNETWORKING_PIN_SSL_CERTIFICATES_ conditions

Fixes #1098
Update documentation re: _AFNETWORKING_PIN_SSL_CERTIFICATES_
Remove reference to _AFNETWORKING_PIN_SSL_CERTIFICATES_
Add adn certificate to Mac example
Update README.md for 'complete documentation' link

http://afnetworking.github.com/AFNetworking is no more.
Fixing -[AFHTTPClient copyWithZone:].
Put the logo back

It's prettier that way.
Merge pull request #1116 from Palleas/patch-1

Put the logo back
Merge pull request #1114 from OliverLetterer/copy-http-client

Fixing -[AFHTTPClient copyWithZone:].
Merge pull request #1113 from raven/master

Update README.md for 'complete documentation' link
[Issue #1115] Only set placeholder image if not nil
Merge branch 'master' of github.com:AFNetworking/AFNetworking
Use new httpbin image request to fix image test.
Merge pull request #1124 from carsonmcdonald/fiximagetest

Use new httpbin image request to fix image test
Fixing broken images in README
Merge branch 'master' of github.com:AFNetworking/AFNetworking
Use new httpbin image request to fix image test.