Create smack-im subproject for XMPP-IM

Move Roster and Chat(Manager) code into their own packages within the
new smack-im subproject.

Apply Manager pattern to Roster.

Fixes SMACK-637.

smack-tcp/src/test/java/org/jivesoftware/smack/tcp/RosterOfflineTest.java

@@ -1,63 +0,0 @@
-/**
- *
- * Copyright the original author or authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.jivesoftware.smack.tcp;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-
-import org.jivesoftware.smack.Roster;
-import org.jivesoftware.smack.SmackException;
-import org.jivesoftware.smack.XMPPException;
-import org.junit.Before;
-import org.junit.Test;
-
-/**
- * Tests the behavior of the roster if the connection is not authenticated yet.
- * 
- * @author Henning Staib
- */
-public class RosterOfflineTest {
-
-    XMPPTCPConnection connection;
-
-    Roster roster;
-
-    @Before
-    public void setup() throws XMPPException, SmackException {
-        this.connection = new XMPPTCPConnection("user", "pass", "example.org");
-        assertFalse(connection.isConnected());
-
-        roster = connection.getRoster();
-        assertNotNull(roster);
-    }
-
-    @Test(expected = SmackException.class)
-    public void shouldThrowExceptionOnCreateEntry() throws Exception {
-        roster.createEntry("test", "test", null);
-    }
-
-    @Test(expected = SmackException.class)
-    public void shouldThrowExceptionOnReload() throws Exception {
-        roster.reload();
-    }
-
-    @Test(expected = SmackException.class)
-    public void shouldThrowExceptionRemoveEntry() throws Exception {
-        roster.removeEntry(null);
-    }
-
-}