mod_http_oauth2: Reject duplicate form-urlencoded parameters Per RFC 6749 section 3.1 > Request and response parameters MUST NOT be included more than once. Thanks to OAuch for pointing out Also cleans up some of the icky behavior of formdecode(), like returning a string if no '=' is included.

This module produces more detailed HTTP logs for Prosodys built-in HTTP
server. The format is similar to that of Apache and go into Prosodys
normal logs at the `info` level.