Add XEP-0191 - Blocking Command implementation

SMACK-731

documentation/extensions/blockingcommand.md

@@ -0,0 +1,63 @@
+Blocking Command
+================
+
+Allows to manage communications blocking.
+
+  * Check push notifications support
+  * Get blocking list
+  * Block contact
+  * Unblock contact
+  * Unblock all
+
+
+**XEP related:** [XEP-0191](http://xmpp.org/extensions/xep-0191.html)
+
+
+Get an instance of Blocking Command Manager
+-------------------------------------------
+
+```
+BlockingCommandManager blockingCommandManager = BlockingCommandManager.getInstanceFor(connection);
+```
+
+
+Check blocking command support
+------------------------------
+
+```
+boolean isSupported = blockingCommandManager.isSupportedByServer();
+```
+
+
+Get block list
+--------------
+
+```
+List<Jid> blockList = blockingCommandManager.getBlockList();
+```
+
+
+Block contact
+-------------
+
+```
+blockingCommandManager.blockContact(jid);
+```
+*jid* is a `Jid`
+
+
+Unblock contact
+---------------
+
+```
+blockingCommandManager.unblockContact(jid);
+```
+*jid* is a `Jid`
+
+
+Unblock all
+-----------
+
+```
+blockingCommandManager.unblockAll();
+```