DRAFT/WIP Update to Smack 4.0.1

This PR is not yet to be merged. Smack 4.0.1 is not yet released and I'd like to discuss a few things first.

I've took the liberty to update Smack to the latest version with the commit, since I don't like the idea of a fragmented Smack (3.2.1-MODIFIED) and would like to concentrate Smack development in one place. This commit creates the org.jivesoftware.smackx.rsm package for initial RSM support, that I'd like to incubate here and once it is finished, move into upstream Smack.

It also appears that you guys work around a bug in Smack's PubSub implementation. It would have been great if this was reported upstream, ie. to me, so that it can be fixed and other benefit from it to.

Smack 4 does not support non-SASL auth, so the relevant code was removed.

I also took the liberty to fix a few javadoc bugs like s/@param/@code/ where appropriate.

I hope to implemented all modifications of your used -MODIFIED Smack version, but since I couldn't find the code I can't be sure. Would be great if someone more involved in buddycloud-media-server could test my changes and report back.

I really like the buddycloud project and it would be great if we (IgniteRealtime Smack) could work closer together. For example, if you write code for an XEP, let me now so that we can get it into Smack. :-) I plan to release Smack 4.0.1 in the next 4-8 weeks.