Add script and link tags

This PR pulls in webjars-locator 0.13 instead of 0.3, and adds link and script tags. 

Usage
=====
You can omit the webjar attribute if you know the path is unique.

Use a javascript file in a JSP
------------------------------
    <w:script webjar="tablesorter" path="jquery.tablesorter.js" />

This produces the following output:

    <script src='/myappcontext/webjars/tablesorter/2.15.5/js/jquery.tablesorter.js'></script>

Use a stylesheet in a JSP
-------------------------
    <w:link webjar="tablesorter" path="theme.default.css" />

This produces the following output:

    <link rel='stylesheet' type='text/css' href='/myappcontext/webjars/tablesorter/2.15.5/css/theme.default.css' />

You can override the media, rel and type attributes.