Update sub-repo license

Author: james34602

Tutorials/LICENSE

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+Copyright 2019-2020 James Fung
+
+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.

Tutorials/README.md

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+# How to build Android audio effect from scratch?
+
+## Example - JamesDSP Engine frame
+Compatibility: Support all Android version from 4.4(Kitkat) to 10.0(Q)
+
+Any signal processing code is not present.
+
+Android audio framework learner that use current repository can play around it and add your own DSP code. I'm pretty sure this repository is a good starting point, you can build your own audio effect engine without download the whole Android source code from Google, while I can't deny AOSP Android code is very useful at reference, but not very useful at program design.
+
+**Description to be continued**
+
+## License
+All codes under this folder is distributed in Apache license.
+
+Main repository GNU license is excluded and not related.