Update 7zip for Windows to latest release and enforce 7zip format when unpacking.

To protect against recently discovered 7zip vulnerabilities we took some precautions.
http://blog.talosintel.com/2016/05/multiple-7-zip-vulnerabilities.html

The Windows version of 7za has been updated to a non-vulnerable version.
We force 7za to only unpack actual 7zip archives.
This should make exploitation of the UDF- and HFS-vulnerabilities in the 7zip tools impossible.

win/7zip/license.txt

@@ -1,14 +1,15 @@
-      7-Zip Command line version
-      ~~~~~~~~~~~~~~~~~~~~~~~~~~
+      7-Zip Extra
+      ~~~~~~~~~~~
       License for use and distribution
       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-      7-Zip Copyright (C) 1999-2010 Igor Pavlov.
+      Copyright (C) 1999-2016 Igor Pavlov.
 
-      7za.exe is distributed under the GNU LGPL license
+      7-Zip Extra files are under the GNU LGPL license.
 
+      
       Notes: 
-        You can use 7-Zip on any computer, including a computer in a commercial 
+        You can use 7-Zip Extra on any computer, including a computer in a commercial 
         organization. You don't need to register or pay for 7-Zip.
 
 
@@ -27,3 +28,4 @@
 
         You can receive a copy of the GNU Lesser General Public License from 
         http://www.gnu.org/
+