tk: Upgrade to 8.6.0

This also fixes the build since tcl is moved to 8.6.0 in OE-Core
The licence has been updated a little

license.terms       2009-11-13 10:38:48.000000000 -0800
license.terms       2012-12-19 07:39:12.000000000 -0800
@@ -1,7 +1,8 @@
 This software is copyrighted by the Regents of the University of
-California, Sun Microsystems, Inc., and other parties.  The following
-terms apply to all files associated with the software unless explicitly
-disclaimed in individual files.
+California, Sun Microsystems, Inc., Scriptics Corporation, ActiveState
+Corporation, Apple Inc. and other parties.  The following terms apply
to
+all files associated with the software unless explicitly disclaimed in
+individual files.

 The authors hereby grant permission to use, copy, modify, distribute,
 and license this software and its documentation for any purpose,
provided
@@ -28,12 +29,12 @@

 GOVERNMENT USE: If you are acquiring this software on behalf of the
 U.S. government, the Government shall have only "Restricted Rights"
-in the software and related documentation as defined in the Federal
+in the software and related documentation as defined in the Federal
 Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2).  If you
 are acquiring the software on behalf of the Department of Defense, the
 software shall be classified as "Commercial Computer Software" and the
 Government shall have only "Restricted Rights" as defined in Clause
-252.227-7013 (c) (1) of DFARs.  Notwithstanding the foregoing, the
+252.227-7013 (b) (3) of DFARs.  Notwithstanding the foregoing, the
 authors grant the U.S. Government and others acting in its behalf
 permission to use and distribute the software in accordance with the
 terms specified in this license.

Signed-off-by: Khem Raj <raj.khem@gmail.com>