Improve packet send and result collecting API

Instead of repeating the same pattern, when sending an IQ get/set packet
and collecting the response

PacketFilter filter = new PacketIDFilter(request.getPacketID()),
PacketCollector collector = connection.createPacketCollector(filter);
connection.sendPacket(reg);
IQ result = (IQ)collector.nextResult(SmackConfiguration.getPacketReplyTimeout());
// Stop queuing results
collector.cancel();
if (result == null) {
    throw new XMPPException("No response from server.");
}
else if (result.getType() == IQ.Type.ERROR) {
    throw new XMPPException(result.getError());
}

the API got redesigned, so that the above code block can be replaced
with

Packet result = connection.createPacketCollectorAndSend(request).nextResultOrThrow();
Fix eclipse formatter settings: indentation.size=4
Activate the jingle subproject and move integration tests

The jingle subproject builds now. This doesn't change that the code is
outdated with regard to the specification and unmaintained for
years. But hopefully this is the first step to change that. :)

The integration tests have been moved into SourceSets of 'core' and
'extensions'.
SMACK-465: XMPPException using Java's wrapped Throwable