Make LoadModule and LoadFile work correctly across restarts (i.e.

by unloading the loaded modules/files, then reloading when the config
file is read again).

Add longer commentary about how to use the module (which could become
a part of the documentation when this module become non-experimental).

Properly report errors during LoadFile.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@80138 13f79535-47bb-0310-9956-ffa450edef68