Upgrading to Smack 4.1.0 API (not working yet)

SASL EXTERNAL needs back porting from Smack 4.0

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
SASL EXTERNAL will be automatically added by Smack

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Use instantShutdown when needed

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>
Merge branch 'master' into smack_4_1_0
Going back to master

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>