Display license on repository top

[ytakashina]

There are already license terms in each file, but adding LICENSE file to the repository root will help users confirm license easily.

// Accord Machine Learning Library
// The Accord.NET Framework
// http://accord-framework.net
//
// Copyright © César Souza, 2009-2017
// cesarsouza at gmail.com
//
// Copyright © Antonino Porcino, 2010
// iz8bly at yahoo.it
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Found

[ytakashina]

Oh, sorry there is a license.txt. However, in GitHub, a shortened license name will be displayed on the repository page if there is a LICENSE file. It would be better.

https://github.com/blog/2252-license-now-displayed-on-repository-overview

[cesarsouza]

Thanks @y-takashina, I didn't know about this GitHub functionality. I will rename the license.txt file to LICENSE so it can be recognized by GitHub.

[ytakashina]

The license doesn't seem displayed in my environment.
The LICENSE in this repository is modified a little. Maybe the modification makes it difficult for the GitHub license picker to detect the license.

[cesarsouza]

Added in release 3.6.0.