cleanup the conditional expression parser for

- improved efficiency and memory footprint
- improved readability
- style
This includes an overhaul of the debugging macros, mostly
that they are not always in the way if one tries to understand
the code ;-)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@101078 13f79535-47bb-0310-9956-ffa450edef68