moved getConfiguration from XMPPConnection to AbstractXMPPConnection
restore  the XMPPConnection parameter in the Roster and added two new methods to the interface.
reformatted files
Merge branch 'get_configuration_visibility' of github.com:BugsBunnyBR/Smack into get_configuration_visibility

Conflicts:
	smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java
	smack-core/src/main/java/org/jivesoftware/smack/XMPPConnection.java