HEI: initial "hello world"

Change-Id: I8d4f1994a58afdf24558bb528de632de0511c75c
diff --git a/hei_user_interface.hpp b/hei_user_interface.hpp
new file mode 100644
index 0000000..345c082
--- /dev/null
+++ b/hei_user_interface.hpp
@@ -0,0 +1,10 @@
+
+#pragma once
+
+// This header provides access to headers and marcros defined by the user
+// application.
+#include <hei_user_defines.hpp>
+
+// The rest of this header contains interfaces that the user application must
+// define.
+