Add Apache license file

Use the same license as for the other projects of tesseract-ocr.
Remove the old COPYING file which included a shortened license text.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

LICENSE

@@ -1,3 +1,4 @@
+
                                  Apache License
                            Version 2.0, January 2004
                         http://www.apache.org/licenses/
@@ -174,3 +175,28 @@
       of your accepting any such warranty or additional liability.
 
    END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

README.md

@@ -53,4 +53,4 @@ With a theory that poor accuracy on test data and over-fitting on training data
 See the [Tesseract wiki](https://github.com/tesseract-ocr/tesseract/wiki/Data-Files) for additional information.
 
 All data in the repository are licensed under the
-Apache-2.0 License, see file [COPYING](COPYING).
+Apache-2.0 License, see file [LICENSE](LICENSE).