SMACK-441 ServiceDiscoveryManager identities should be non-static and kept in a Set to allow multiple identities as per XEP-0030

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@13783 b35dd754-fafc-0310-a699-88a17e54d16e
SNMACK-458 Managers should be kept on disconnects

Smack's Managers should not remove itself when the connection is closed
or should re-add themselfs if the connection get reconnected.

This should also fix some NPE's.

We are currenlty going with two different designs of Manager: 1. The one
with WeakReferences (SDM, EntityCapsManager) and 2. the one where the
managers remove their listeners on connectionClosed() *and*
connectionClosedOnError(), and later add their listeners on
reconnectionSuccessful().

Conflicts:
	source/org/jivesoftware/smackx/ServiceDiscoveryManager.java
	source/org/jivesoftware/smackx/bytestreams/socks5/Socks5BytestreamManager.java
	source/org/jivesoftware/smackx/commands/AdHocCommandManager.java
	source/org/jivesoftware/smackx/ping/PingManager.java