Change "muust be compiled with ARC" to "must be compiled with ARC"

Fix a typo in the error message if the user attempts to compile with project without ARC.
Fix references to wrong header file in README.
Merge pull request #153 from square/federman/kill_warnings

Kill Xcode 5.1 warnings
Remove errant assert(NO) in _sendFrameWithOpcode
use 'normal closure' close code by default, fixes #127

SocketRocket uses the invalid close code -1 as the value in the default close method. In addition to being invalid, it causes issues when communicating with some libraries. See section 11.7 WebSocket Close Code Number Registry in the WebSocket Protocol RFC 6455 for more detail.
Use Apple's provided base64 implementation.
Fix Xcode 5.1 project warnings.
Merge pull request #160 from square/kve/kve/RI-3784

[Master] Use Apple's provided base64 implementation.
Fix size conversion warnings.
Merge pull request #162 from square/alanf/fix-size-conversion-warnings

Fix size conversion warnings.

Reviewed by @firestone.
Moved SRStatusCode to header file for public use of status code values
Switched SocketRocket methods to use SRStatusCode instead of NSInteger
Changed 0 code to 1001 going away
Fixed base64Encoding deprecation, added the actual HTTP status code with key ‘HTTPResponseStatusCode’ in the NSError userInfo dictionary on status codes of >= 400, gives you the ability to see why a connection fails such as a 401 authentication failure
Merge pull request #161 from square/af/fix-code-51-warnings

Fix Xcode 5.1 project warnings.
Go 1 has been released. Update README :)
Merge pull request #180 from andybons/patch-1

Go 1 has been released. Update README :)
Merge pull request #112 from jcoleman/master

Fix references to wrong header file in README.
Merge pull request #93 from dmitric/patch-1

Change "muust be compiled with ARC" to "must be compiled with ARC"
Removed enforcement of the SRStatusCode enum for status code arguments