adapt COPYING files to new example code license

Author: farindk

COPYING

@@ -1,9 +1,7 @@
-The library `libheif` is distributed under the terms of the GNU Lesser
-General Public License. The sample applications are distributed under
-the terms of the GNU General Public License.
+* The library `libheif` is distributed under the terms of the GNU Lesser General Public License.
+* The sample applications are distributed under the terms of the MIT License.
 
-License texts below and in the `COPYING` files of the corresponding
-subfolders.
+License texts below and in the `COPYING` files of the corresponding subfolders.
 
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@@ -851,3 +849,23 @@ Public License instead of this License.  But first, please read
 <http://www.gnu.org/philosophy/why-not-lgpl.html>.
 
 ----------------------------------------------------------------------
+
+                             MIT License
+
+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.