Add README with license.

Peter Amstutz · Peter Amstutz · commit d3e50631b2f6 · 2016-02-10T11:12:50.000-05:00
diff --git a/presentations/README.md b/presentations/README.md
@@ -0,0 +1,3 @@
+Documents in this directory are licensed CC BY-SA:
+
+https://creativecommons.org/licenses/by-sa/4.0/

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+Documents in this directory are licensed CC BY-SA:`
	`2`	`+`
	`3`	`+https://creativecommons.org/licenses/by-sa/4.0/`