adding norwegian translation

Initialize the xmpp connection config in a background thread. On android > 3.x network operations on the main thread crash the application. This move the dns request made by the ConnectionConfiguration in another thread by lazily initializing the XMPPConnection

Complete the avatar provider to support insert update and delete. It is now usable following the standard Android interface.

Fix bug when creating contact. The contact is created asynchronously so we cannot try to get it immediatly. As a consequence the method IRoster.createContact now return a boolean.