Added acceptance test

Author: mfarah

precheckin.sh

@@ -1,3 +1,13 @@
+#!/bin/bash
+
 gofmt -w .
 golint
 go test
+
+# acceptance test
+X=$(go run yaml.go  sample.yaml b.c)
+
+if [ $X != 2 ]
+  then
+	echo "Failed acceptance test: expected 2 but was $X"
+fi