Spec tidy-up
    
    - Use author-independent source URL
    - Classify buildreqs by usage
    - Drop redundant %{?perl_default_filter}
    - Drop redundant specification of compiler flags for noarch package
    - Use DESTDIR rather than PERL_INSTALL_ROOT
    - Simplify find command using -delete
    - Don't need to remove empty directories from the buildroot
    - Fix permissions verbosely
    - Package the Changes file