Adding new delegate method for XMPPStream - xmppStreamDidFilterStanza
Minor bug fix for XMPPBandwidthMonitor - should start monitoring bandwidth immediately upon TCP connect, not post XMPP handshake.
Minor optimization for XMPPIDTracker - only fetch the elementID once.
Bug fix for edge case in XMPPStreamManagement - counts would be incorrect if a delegate filtered an incoming stanza.