Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

1.  Redistributions in source code must retain the accompanying
    copyright notice, this list of conditions, and the following
    disclaimer.

2.  Redistributions in binary form must reproduce the accompanying
    copyright notice, this list of conditions, and the following
    disclaimer in the documentation and/or other materials provided
    with the distribution.

3.  Names of the copyright holders must not be used to endorse or
    promote products derived from this software without prior
    written permission from the copyright holders.

4.  If any files are modified, you must cause the modified files to
    carry prominent notices stating that you changed the files and
    the date of any change.

Disclaimer

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS "AS IS" AND
  ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  SUCH DAMAGE.