Get rid of the global trace_add in favor of specific trace functions tailored...

Get rid of the global trace_add in favor of specific trace functions tailored to the server run phase and callback context. Add the final trace function (for no context) and start moving the EXAMPLE_LOG_EACH stuff to ap_log_perror instead of directly writing to stdout.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@492376 13f79535-47bb-0310-9956-ffa450edef68