Enhance plain-servlet, and verify the integration test can pass tomcat6, 7, 8, 9. This is a companion change of HotswapProjects/HotswapAgent#470 and HotswapProjects/HotswapAgent#471
Also verify jetty7, jetty8, jetty9 work too, but right now HotswapAgent stops working with jetty 10 and later.
Enhance plain-servlet, and verify the integration test can pass tomcat6, 7, 8, 9. This is a companion change of HotswapProjects/HotswapAgent#470 and HotswapProjects/HotswapAgent#471
Also verify jetty7, jetty8, jetty9 work too, but right now HotswapAgent stops working with jetty 10 and later.