Log Message:

version -> 0.15.0

   Major changes

     pkg_grep_summary: in order to support summaries for multi-variant
     packages it is strongly recommented to use 'fvalue' variable in
     condition, not $2. Man page and README update accordingly.

     pkg_cmp_summary: -m option added for comparing summaries for
     multi-variant packages
     (PKGPATH=category/name:variable_assignments format).

pkg_cmp_summary -m implies -p