Cleanup licensing

Add text of BOOST and ISC to source repo and clarify sources under each
in the README

LICENSE.BOOSTv1_0

@@ -0,0 +1,23 @@
+Boost Software License - Version 1.0 - August 17th, 2003
+
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

LICENSE.ISC

@@ -0,0 +1,10 @@
+Permission to use, copy, modify, and/or distribute this software for any purpose 
+with or without fee is hereby granted, provided that the above copyright notice 
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH 
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND 
+FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, 
+OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA 
+OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, 
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

LICENSE.README

@@ -1,8 +1,9 @@
 The majority of KiCad's source code is developed and distributed under the terms
 of the GPLv3 or later. However, It does include some third-party code licensed
-under AGPLv3 or later.
+under AGPLv3 or later as well as sections licensed under the BOOST license v1.0
+and portions licensed under the ISC license.
 
-Both licenses are compatible, but a combined works as is will be governed under
+These licenses are compatible, but a combined works as is will be governed under
 the terms of the AGPLv3 (or later). This includes any binary distribution of the
 KiCad EDA suite by the KiCad project or any third party, e.g. Linux distributor.
 
@@ -10,4 +11,9 @@ You are free to use the *sources* under the terms of their respective licenses.
 
 Licensed under AGPLv3 (or later):
 - TTL [https://www.sintef.no/projectweb/geometry-toolkits/ttl/], sources in include/ttl/*
+Licensed under BOOSTv1:
+- libcontext [https://github.com/boostorg/context], sources in common/system/libcontext.cpp
+Licensed under ISC:
+- portions of code in include/geometry/polygon_triangulation.h
 Licensed under GPLv3 (or later):
+- All remaining code not listed above

common/system/libcontext.cpp

@@ -9,7 +9,7 @@
     Minor modifications by Tomasz Wlostowski 2016.
 
  Distributed under the Boost Software License, Version 1.0.
-      (See accompanying file LICENSE_1_0.txt or copy at
+      (See accompanying file LICENSE.BOOSTv1_0.txt or copy at
             http://www.boost.org/LICENSE_1_0.txt)
 
 */