• Adds removal of outdated vendor prefixes based on browser support.
• Addresses an issue where relative path separators were converted to
  backslashes on Windows.
• cssnano will now detect previous plugins and silently disable them when the
  functionality overlaps. This is to enable faster interoperation with cssnext.
• cssnano now exports as a PostCSS plugin. The simple interface is exposed
  at cssnano.process(css, opts) instead of cssnano(css, opts).
• Improved URL detection when using two or more in the same declaration.
• node 0.10 is no longer officially supported.