added license

Author: Damien Laidin

LICENSE.md

@@ -0,0 +1,14 @@
+# Chirp License
+
+This software is copyright © 2011-2019, Asio Ltd. All rights reserved.
+
+This software is provided under license from Asio Ltd. It is to be used only in accordance with our [Fair Use Policy](https://public.chirp.io/docs/Chirp+Fair+Use+Licence+Agreement.pdf)
+
+Chirp retains the right to revoke access or use of our technology without limitation. The above copyright notice and this permission notice shall be included in all copies or substantial portions of the software.
+
+Chirp acknowledges that the following third-party open source software is used and covered by these licenses (Apache-2.0 and BSD-3)
+
+- [Arm mBedTLS License](https://github.com/ARMmbed/mbedtls/blob/development/apache-2.0.txt)
+- [Arm CMSIS License](https://github.com/ARM-software/CMSIS_5/blob/develop/LICENSE.txt)
+- [ESP DSP License](https://github.com/espressif/esp-dsp/blob/master/LICENSE)
+- [libtomcrypt License](https://github.com/libtom/libtomcrypt/blob/develop/LICENSE)