修复媒体共享模块权限，只有老师有开启和停止的权限，修复学生退出课堂时停止了屏幕共享的bug

@@ -33,7 +33,7 @@ import QuestionApe from 'apes/QuestionApe';
 import UTF8 from 'utf-8';
 
 let loger = Loger.getLoger('McuClient');
-let _sdkInfo = { "version": "v1.37.1.20170622", "author": "www.3mang.com" };
+let _sdkInfo = { "version": "v1.37.2.20170622", "author": "www.3mang.com" };
 
 //APE
 let _sass;

@@ -171,17 +171,6 @@ class QuestionApe extends Ape {
                         loger.log("更新答题数据");
                         if(GlobalConfig.isHost){
                             ////老师，只统计数据，不答题
-                            ////先判断时间是否超时
-                            //let timeDistance=EngineUtils.creatTimestamp()-model.timestamp;
-                            //loger.log("答题卡显示倒计时->timeDistance:"+timeDistance);
-                            //timeDistance=model.timeLimit-timeDistance;
-                            //if(timeDistance<=0){
-                            //    //答题卡时间到，需要停止
-                            //    loger.log("答题卡时间到->需要停止");
-                            //    this.stopQuestion(model);
-                            //}else {
-                            //    this.getQuestionResult(model);
-                            //}
                             this.getQuestionResult(model);
                         }else if(GlobalConfig.isNormal) {
                             //学生->如果自己已经提交过答案就不需要再显示

@@ -235,9 +235,12 @@ class VideoApe extends Ape {
         if(_param&&_param.type=='live'){
             publishType='live';
         }
-        //获取屏幕共享推流的地址
-        let shareResult=this.mediaModule.getMediaPublishPathForScreenShare(this.shareApe.channelId,publishType);
-        this.shareApe.publish(shareResult);
+        //老师能开启屏幕共享
+        if(GlobalConfig.isHost) {
+            //获取屏幕共享推流的地址
+            let shareResult = this.mediaModule.getMediaPublishPathForScreenShare(this.shareApe.channelId, publishType);
+            this.shareApe.publish(shareResult);
+        }
     }
 
     //停止桌面共享推流
@@ -247,11 +250,15 @@ class VideoApe extends Ape {
             loger.warn(GlobalConfig.getCurrentStatus());
             return {"code": ApeConsts.RETURN_FAILED, "data": "已经断开连接"};
         }
-        let channelInfo=this.shareApe.getDefaultChannelInfo();
-        channelInfo.status=ApeConsts.CHANNEL_STATUS_RELEASED;
-        this.sendTableUpdateHandler(channelInfo);
+        //只有老师能停止屏幕共享
+        if(GlobalConfig.isHost){
+            let channelInfo=this.shareApe.getDefaultChannelInfo();
+            channelInfo.status=ApeConsts.CHANNEL_STATUS_RELEASED;
+            this.sendTableUpdateHandler(channelInfo);
+
+            this.shareApe.stopPublish();
+        }
 
-        this.shareApe.stopPublish();
     }
 
     //=============================屏幕共享 end=================================================