lua_request.c: Add support for parsing multipart form data via r:parsebody....

lua_request.c: Add support for parsing multipart form data via r:parsebody. This is a bit RFC-centric, suggestions are most welcome.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1420286 13f79535-47bb-0310-9956-ffa450edef68