The Pastel SVG icon set Created by Michael Buckley is
licensed under the

Creative Commons Attribution-Share Alike 3.0 Unported
   http://creativecommons.org/licenses/by-sa/3.0/

Additionally the following restrictions are imposed

  1. If you put Pastel SVG on another web host in modified
  form you must provide a link back to the Pastel SVG homepage
          http://codefisher.org/pastel-svg/
  2. Commercial users of the Pastel SVG are requested to ask
  permission for use of the icons before they do so.  The
  author may expect some kind of reimbursement for the effort
  put into creating the icon set.  This maybe be something as
  simple as a link back to the before mentioned home page.
  3.  If the Pastel SVG are used in an application or on a
  web site.  A link back to the home page is expected.
  4.      THIS WORK CAN NOT BE CLAIMED AS YOUR OWN

The SVG images from which the PNGs are created are closed source
however they may be requested at a price.