fix shebang for windows installation

Author: euclio

instant-markdown-d

@@ -1,5 +1,4 @@
-#!/bin/sh
-':' //; exec "`command -v nodejs || command -v node`" "$0"
+#!/usr/bin/env node
 
 var MarkdownIt = require('markdown-it');
 var hljs = require('highlight.js');