move markdown example from /plugins to /examples

examples/markdown.md

@@ -0,0 +1,36 @@
+# Markdown Demo
+
+
+
+## External 1.1
+
+Content 1.1
+
+Note: This will only appear in the speaker notes window.
+
+
+## External 1.2
+
+Content 1.2
+
+
+
+## External 2
+
+Content 2.1
+
+
+
+## External 3.1
+
+Content 3.1
+
+
+## External 3.2
+
+Content 3.2
+
+
+## External 3.3
+
+![External Image](https://s3.amazonaws.com/static.slid.es/logo/v2/slides-symbol-512x512.png)