Added two functions get_owning_module and get_owning_config for
looking up the module and config for something, e.g. a Tag object or
some module callback function.
Added functions for doing request tracing in the debug log. Define
REQUEST_TRACE for this.
Changed the compatibility Parser.C to _Parser.C since it's too hard in
Pike currently to get at the global Parser module when there's
something else around with the same name.