add license

LICENSE.md

@@ -0,0 +1,11 @@
+**You may:**
+
+* Use this software for yourself;
+* Use this software for a company;
+* Modify this software, as long as you:
+  * Publish the changes on GitHub as an open-source & linked fork;
+  * Don't remove any links to the original project or donation pages;
+
+**You may not:**
+
+* Use this software in a commercial product without a license from the original author;