Struts 2 support for Dynacache

Basic Dynacache servlet caching will work with Struts 2; however Dynacache support for struts 2 is tricky since Struts2 is not backwards compatible with Struts1 and there is no ActionServlet in Struts 2.

Please note
- Dynamic caching may NOT always work with ALL the cachespec.xml combinations offered by Dynacache.
- Customer will need to set the  com.ibm.ws.webcontainer.invokefilterscompatibility  webcontainer custom property to true to get strut2 fragment caching to work.
- When caching Struts 2 output, the cache entries will need to be written  for the appropriate JSPs and servlet to be served by the application.