3.3.4接口变化列表
''-''代表原来api，''+''代表修改后的api。 @Deprecated代表已过时的api，后面会带着替代的api

新增加接口EMChatManager
<code>
EMChatManager:
+     public void recallMessage(EMMessage message);
+     public void aysncRecallMessage(final EMMessage message,
+                                   final EMCallBack callback);

+    public EMCursorResult<EMMessage> fetchHistoryMessages(String conversationId, EMConversationType type, int pageSize,
+                                    String startMsgId);

+    public void asyncFetchHistoryMessage(final String conversationId, final EMConversationType type, final int pageSize,
+                                   final String startMsgId, final EMValueCallBack<EMCursorResult<EMMessage>> callBack);

+    public List<String> getSelfIdsOnOtherPlatform();
</code>

新增加接口EMContactManager
<code>
EMContactManager:
+    public List<String> getSelfIdsOnOtherPlatform();
+    public void aysncGetSelfIdsOnOtherPlatform(final EMValueCallBack<List<String>> callback);
</code>

新增加接口EMMessage
<code>
EMMessage:
+    public String conversationId();
</code>

新增加接口EMMessageListener
<code>
EMMessageListener:
+    public void onMessageRecalled(List<EMMessage> messages);
</code>

新增加接口EMFileMessageBody
<code>
EMFileMessageBody:
+   public void setFileLength(long length) 
+   public void setDownloadStatus(EMDownloadStatus status) 
</code>

新增加类EMHWPushReceiver
<code>
+   public class EMHWPushReceiver
</code>