Use background task names when possible (ios7+) and use better names for them

src/backgroundtask.m

@@ -22,11 +22,19 @@
 
 unsigned int belle_sip_begin_background_task(const char *name, belle_sip_background_task_end_callback_t cb, void *data){
 	UIApplication *app=[UIApplication sharedApplication];
-	UIBackgroundTaskIdentifier bgid=[app beginBackgroundTaskWithExpirationHandler:^{
+	UIBackgroundTaskIdentifier bgid = UIBackgroundTaskInvalid;
+	void (^handler)() = ^{
 		cb(data);
-	}];
+	};
+
+	if([app respondsToSelector:@selector(beginBackgroundTaskWithName:expirationHandler:)]){
+		bgid = [app beginBackgroundTaskWithName:[NSString stringWithUTF8String:name] expirationHandler:handler];
+	} else {
+		bgid = [app beginBackgroundTaskWithExpirationHandler:handler];
+	}
+
 	if (bgid==UIBackgroundTaskInvalid){
-		belle_sip_error("Could not start background task.");
+		belle_sip_error("Could not start background task %s.", name);
 		return 0;
 	}
 	return (unsigned int)bgid;

src/channel.c

@@ -768,7 +768,7 @@ static void channel_on_send_background_task_ended(belle_sip_channel_t *obj){
 
 static void channel_begin_send_background_task(belle_sip_channel_t *obj){
 	if (obj->bg_task_id==0){
-		obj->bg_task_id=belle_sip_begin_background_task("belle-sip channel in progress",(void (*)(void*))channel_on_send_background_task_ended, obj);
+		obj->bg_task_id=belle_sip_begin_background_task("belle-sip send channel",(void (*)(void*))channel_on_send_background_task_ended, obj);
 		if (obj->bg_task_id) belle_sip_message("channel [%p]: starting send background task with id=[%x].",obj,obj->bg_task_id);
 	}
 }
@@ -788,7 +788,7 @@ static void channel_on_recv_background_task_ended(belle_sip_channel_t *obj){
 
 static void channel_begin_recv_background_task(belle_sip_channel_t *obj){
 	if (obj->recv_bg_task_id==0){
-		obj->recv_bg_task_id=belle_sip_begin_background_task("belle-sip channel in progress",(void (*)(void*))channel_on_recv_background_task_ended, obj);
+		obj->recv_bg_task_id=belle_sip_begin_background_task("belle-sip recv channel",(void (*)(void*))channel_on_recv_background_task_ended, obj);
 		if (obj->recv_bg_task_id) belle_sip_message("channel [%p]: starting recv background task with id=[%x].",obj,obj->recv_bg_task_id);
 	}
 }

src/http-provider.c

@@ -405,7 +405,7 @@ int belle_http_provider_send_request(belle_http_provider_t *obj, belle_http_requ
 	fix_request(req);
 
 	if( req->background_task_id != 0){
-		req->background_task_id = belle_sip_begin_background_task("http", belle_http_end_background_task, req);
+		req->background_task_id = belle_sip_begin_background_task("belle-sip http", belle_http_end_background_task, req);
 	}
 
 	belle_sip_channel_queue_message(chan,BELLE_SIP_MESSAGE(req));