Upstream master

There are 2 commits:
1. Modified the log content and format in JettyHandler so that every http request, as well as its query string and return code are logged in level INFO. I believe that will help monitor and analysis of the server.
2. Add multipart/form-data support in JettyHandler, so that Servlet 3.0 API getPart(String) and getParts, which can deal with form file uploading, can be used directly.