Adds abilities to monster cards.

Adds CommonMark dependency and CommonMarkHelper to render it to html.

app/src/main/java/com/majinnaibu/monstercards/helpers/CommonMarkHelper.java

@@ -0,0 +1,38 @@
+package com.majinnaibu.monstercards.helpers;
+
+import org.commonmark.node.Document;
+import org.commonmark.node.Node;
+import org.commonmark.node.Paragraph;
+import org.commonmark.parser.Parser;
+import org.commonmark.renderer.NodeRenderer;
+import org.commonmark.renderer.html.HtmlNodeRendererContext;
+import org.commonmark.renderer.html.HtmlNodeRendererFactory;
+import org.commonmark.renderer.html.HtmlRenderer;
+
+public final class CommonMarkHelper {
+    private static final class MyNodeRendererFactory implements HtmlNodeRendererFactory {
+
+        @Override
+        public NodeRenderer create(HtmlNodeRendererContext context) {
+            return null;
+        }
+    }
+
+    public static String toHtml(String rawCommonMark) {
+        Parser parser = Parser.builder().build();
+        Node document = parser.parse(rawCommonMark);
+        Node parent1 = document.getFirstChild();
+        Node parent2 = document.getLastChild();
+        if (parent1 == parent2 && parent1 instanceof Paragraph) {
+            document = new Document();
+            Node child = parent1.getFirstChild();
+            while(child != null) {
+                Node nextChild = child.getNext();
+                document.appendChild(child);
+                child = nextChild;//child.getNext();
+            }
+        }
+        HtmlRenderer renderer = HtmlRenderer.builder().build();
+        return renderer.render(document);
+    }
+}