Fixed not valid self-closing script tags

Self closing ```<script>``` tag are not allowed in HTML5, and this yelds to a non-parseable html file (head).

Example:
```
Error: Self-closing syntax (/>) used on a non-void HTML element. Ignoring the slash and treating as a start tag.
<script type="text/javascript" src="js/lib/jquery/jquery.min.js" />
```
Tested [here](http://html5.validator.nu/).