Generate and install .conf files

Generate and install .conf files
  (with heavy lifting from tdonovan!).

Install sample docroot (if the top directory doesn't exist).

Change installation of error and icons directories to match
Unix -- only if the top directory doesn't exist.

Provide a simple Perl script to help with non-standard copy
semantics used by the install.

THIS ADDS PERL AS A BUILD PREREQ.  (The VisualStudio-specific
Windows build system required it too.)

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1518376 13f79535-47bb-0310-9956-ffa450edef68