tweaks/fixes in about://tracing performance data generator (press and hold 'p' in example browser, release 'p' will save the file 'timingsX.json')

examples/ExampleBrowser/OpenGLExampleBrowser.cpp

@@ -200,6 +200,11 @@ struct btTimings
 
 #else
          
+			
+			if (startTime>endTime)
+			{
+				endTime = startTime;
+			}
             unsigned int startTimeRem1000 = startTime%1000;
             unsigned int endTimeRem1000 = endTime%1000;
 
@@ -238,6 +243,7 @@ struct btTimings
             
             char newname[1024];
 			static int counter2=0;
+         
             sprintf(newname,"%s%d",name,counter2++);
 			fprintf(gTimingFile,"{\"cat\":\"timing\",\"pid\":1,\"tid\":%d,\"ts\":%" PRIu64 ".%s ,\"ph\":\"B\",\"name\":\"%s\",\"args\":{}},\n",
 				threadId, startTimeDiv1000,startTimeRem1000Str, newname);