resolves MDXMLINT-17 added api command xml_curl (takes debug_on and debug_off as params) that enables and disables keeping the lookup files around for debug reasons.

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@6356 d0543943-73ff-0310-b7d9-9358b9ac24b2