Added iterator interface to API, removed cmark_walk.

* Added `iterator.c`, `iterator.h`.
* Removed `cmark_walk`.
* Replaced `cmark_walk` with iterator in HTML renderer.
* Replaced API test for `cmark_walk` with simple iterator test.

1 files changed, 21 insertions, 0 deletions

diff --git a/src/iterator.h b/src/iterator.h
new file mode 100644
index 0000000..bf53112
--- /dev/null
+++ b/src/iterator.h
@@ -0,0 +1,21 @@
+#ifndef CMARK_ITERATOR_H
+#define CMARK_ITERATOR_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "cmark.h"
+#include "node.h"
+
+struct cmark_iter {
+	cmark_node       *current;
+	cmark_node       *root;
+	cmark_event_type event_type;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif