Revert "Disable WebSockets on master"

This reverts commit faa97c4af8d4014f3f1ea10f75f7b0092d12546e.
WebSockets connection methods
PublicKeyPinning
SocketRocket fork with ping pong
Closing socket in the background properly
WebSocket integration
Merge branch 'WebSockets'

Conflicts:
	TextSecureiOS.xcodeproj/project.pbxproj
	TextSecureiOS/MessagesManager/TSMessagesManager.mm