tools addition to automate setting up windows toolchain

tools/win/toolchain/7z/LICENSE

Index: tools/win/toolchain/7z/LICENSE
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+  7-Zip
+  ~~~~~
+  License for use and distribution
+  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+  7-Zip Copyright (C) 1999-2012 Igor Pavlov.
+
+  Licenses for files are:
+
+    1) 7z.dll: GNU LGPL + unRAR restriction
+    2) All other files:  GNU LGPL
+
+  The GNU LGPL + unRAR restriction means that you must follow both 
+  GNU LGPL rules and unRAR restriction rules.
+
+
+  Note: 
+    You can use 7-Zip on any computer, including a computer in a commercial 
+    organization. You don't need to register or pay for 7-Zip.
+
+
+  GNU LGPL information
+  --------------------
+
+    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 can receive a copy of the GNU Lesser General Public License from 
+    http://www.gnu.org/
+
+
+  unRAR restriction
+  -----------------
+
+    The decompression engine for RAR archives was developed using source 
+    code of unRAR program.
+    All copyrights to original unRAR code are owned by Alexander Roshal.
+
+    The license for original unRAR code has the following restriction:
+
+      The unRAR sources cannot be used to re-create the RAR compression algorithm, 
+      which is proprietary. Distribution of modified unRAR sources in separate form 
+      or as a part of other software is permitted, provided that it is clearly
+      stated in the documentation and source comments that the code may
+      not be used to develop a RAR (WinRAR) compatible archiver.
+
+
+  --
+  Igor Pavlov
+