Make XmlStringBuilder equals() CharSequence aware

The minimal condition in order to check equality in XmlStringBuilder is
that 'other' implements the CharSequence interface. Not as it was
previously, that it's also a XmlStringBuilder.

This allows junit's assertEquals() to be used (to a certain extend).
Make FaultTolerantNegotiator respect packetReplyTimeout
Fix FileTransferManager invoking request listeners

those need to be called asynchronously.

Also add a small API for that.
Make ServiceDiscoveryManager use constant PacketFilters
SDM: Follow guidelines, perform put() where get() is performed
Merge branch 'master' into xep198
Filetransfer API should not wrap IOException

into SmackException.
Merge branch 'master' into xep198