rewritemaps are identified by name. Store 'em in a hash rather than

an array. This is more naturally, efficient (mostly) and better
readable.
Leave deep indentations for now (better diff).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@100794 13f79535-47bb-0310-9956-ffa450edef68