Added reference to Pillow to COPYING

[radarhere]

Keeping it up to date with the changes from #1793, and in sync with the rest of the LICENSE file.

[aclark4life]

Thx

[wiredfool]

So, the thing about this one is that "MIT-like license" means less than nothing when applied to legal language.

Specifically, this clause (noting the "and without fee" part):

Permission to use, copy, modify, and distribute this software and its associated 
documentation for any purpose and without fee is hereby granted

Is not MIT like. I'm not entirely sure what it does mean, but it dates back to the PIL license, and it is significantly less free than any of the usual open source licenses.

The corresponding section of the MIT license is:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and   
associated documentation files (the "Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to
the following conditions:

and the Python license is:

2. Subject to the terms and conditions of this License Agreement, PSF hereby
grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
analyze, test, perform and/or display publicly, prepare derivative works,
distribute, and otherwise use Python 2.7.12 alone or in any derivative
version, provided, however, that PSF's License Agreement and PSF's notice of
copyright, i.e., "Copyright © 2001-2016 Python Software Foundation; All Rights
Reserved" are retained in Python 2.7.12 alone or in any derivative version
prepared by Licensee.  

[aclark4life]

It also broke the build :-) (Not sure why)

[hugovk]

The build broke due to a third-party issue: eliben/pycparser#147, perfectly timed for release day :)

Here's a workaround: PR #2143.