Simple example of secp256k1 library

Revision:
3:048e2964821b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/secp256k1-embedded.lib	Sun May 03 20:54:37 2020 +0000
@@ -0,0 +1,1 @@
+https://github.com/diybitcoinhardware/secp256k1-embedded/#b89c867541fa1f7a822393345d40b4c953e28a19