Fixed saving logger level issue.
Improved handling connectivity issues. https://github.com/openpeer/opios/issues/272
Added Reachibility and OfflineMessanger, classes for handling conection status changes.
Updated headers
Improved backgrounding and APNS logs.
Push notification is sent using NSURLSession
Enabled sending push notification when app goes to background. Sending messages that were tried to sent while account wasn't in ready state.
Updated logs for sending push notification.
Merge commit '04320d50a8c96be38f5b5d788da3ed59bc2e7bec' into feature-20140505-no-connection-fix

Conflicts:
	Samples/OpenPeerSampleApp/OpenPeerSampleApp.xcodeproj/project.pbxproj
	Samples/OpenPeerSampleApp/OpenPeerSampleApp/LoginManager.m
	Samples/OpenPeerSampleApp/OpenPeerSampleApp/MessageManager.m
	Samples/OpenPeerSampleApp/OpenPeerSampleApp/OpenPeer.m
	Samples/OpenPeerSampleApp/OpenPeerSampleApp/SessionManager.m
	openpeer-ios-sdk/source/HOPCall.mm

Fixed error when messages are not delivered after return from background.
Merge branch '20140401-dev-stable' into feature-20140505-no-connection-fix

Conflicts:
	Samples/OpenPeerSampleApp/OpenPeerSampleApp/APNSManager.m
	libs/op
Fixed bugs after latest merge. Code cleanup.
Fixed build error for OpenPeerSampleApp target.
fixed open peer sample apns logo