api: Add go files

I know this is a huge commit, but I can't be bothered to check
this in part by part.

api/commenter_session_new_test.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestCommenterSessionNewBasics(t *testing.T) {
+	failTestOnError(t, setupTestEnv())
+
+	if _, err := commenterSessionNew(); err != nil {
+		t.Errorf("unexpected error creating new session: %v", err)
+		return
+	}
+}