Skype Limited BSD 3-clause license

The Praat source code contains a copy of the SILK software (see Acknowledgments). Here is the Skype Limited license text:

`Copyright (c) 2006-2011 Skype Limited. All rights reserved.
` `
` `Redistribution and use in source and binary forms, with or without
` `modification, are permitted provided that the following conditions
` `are met:
` `
` `- Redistributions of source code must retain the above copyright notice,
` `this list of conditions and the following disclaimer.
` `
` `- Redistributions in binary form must reproduce the above copyright
` `notice, this list of conditions and the following disclaimer in the
` `documentation and/or other materials provided with the distribution.
` `
` `- Neither the name of Internet Society, IETF or IETF Trust, nor the
` `names of specific contributors, may be used to endorse or promote
` `products derived from this software without specific prior written
` `permission.
` `
` `THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
` `AND ANY EXPRESS 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 OWNER OR CONTRIBUTORS 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.
`