Add reference links support

This commit resolves #184

lib/parse/lex.js

@@ -118,6 +118,10 @@ function lexPage(src) {
 
         return sections;
     }, [])
+    .map(function(section) {
+        section.links = nodes.links;
+        return section;
+    })
     .value();
 }
 

lib/parse/page.js

@@ -12,10 +12,9 @@ var lnormalize = require('../utils/lang').normalize;
 // Render a section using our custom renderer
 function render(section, _options) {
     // Copy section
+    var links = section.links;
     section = _.toArray(section);
-
-    // marked's Render expects this, we don't use it yet
-    section.links = {};
+    section.links = links;
 
     // Build options using defaults and our custom renderer
     var options = _.extend({}, marked.defaults, {