LibHTML: Start working on a simple HTML library.

I'd like to have rich text, and we might as well use HTML for that. :^)

LibHTML/Dump.cpp

@@ -0,0 +1,26 @@
+#include <LibHTML/Document.h>
+#include <LibHTML/Dump.h>
+#include <LibHTML/Element.h>
+#include <LibHTML/Text.h>
+#include <stdio.h>
+
+void dump_tree(Node& node)
+{
+    static int indent = 0;
+    for (int i = 0; i < indent; ++i)
+        printf("   ");
+    if (node.is_document()) {
+        printf("*Document*\n");
+    } else if (node.is_element()) {
+        printf("<%s>\n", static_cast<Element&>(node).tag_name().characters());
+    } else if (node.is_text()) {
+        printf("\"%s\"\n", static_cast<Text&>(node).data().characters());
+    }
+    ++indent;
+    if (node.is_parent_node()) {
+        static_cast<ParentNode&>(node).for_each_child([](Node& child) {
+            dump_tree(child);
+        });
+    }
+    --indent;
+}