fix connected property

set connected property in on_connect callback based on the return code
value.

fixes #8
Update Xcode project settings
add cleanSession support
remove deployment target
bump ios.platform to 6.0

required to use dispatch_queue_t as regular Objective-C (for ARC
support)
add deployment target 6.0
add back mosquitto's WITH_THREADING preprocessor macro

removed by mistake in 0c0c013
Fix potential memory issue for applications with high throughput.
Serious bug in MQTTKit.m

Serious bug here, which tied up my server for a week.  initWithClientId takes BOOL cleanSession as parameter, which is almost always set to YES.  However, when it sends it to mosquito_new(), it sends the class property, self.cleanSession, which is not initialized, thus is always NO.  Using this code sets durable clients in the file, and causes the transmit queue to clog up waiting for those clients to sign in again and get their messages.
Merge pull request #4 from scapegoat4U/patch-1

Serious bug in MQTTKit.m
Merge branch 'master' into TLS_support

Conflicts:
	MQTTKit.xcodeproj/project.pbxproj
	MQTTKitTests/MQTTKitTests.m