Adding MIT license

The tinyspline library is under MIT, so needs to be included in our
license bundle.

LICENSE.MIT

@@ -0,0 +1,17 @@
+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:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+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 AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

LICENSE.README

@@ -1,7 +1,7 @@
 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 as well as sections licensed under the BOOST license v1.0
-and portions licensed under the ISC license.
+under AGPLv3 or later as well as sections licensed under the BOOST license v1.0,
+the ISC license and the MIT license.
 
 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
@@ -15,6 +15,8 @@ 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 MIT:
+- tinyspline_lib in dxflib_qcad/tinyspline_lib
 Licensed under CC-BY-SA-4.0:
 - All the demo files provided in demos/*
 Licensed under GPLv3 (or later):