Allow <style> and <script> tags to be unformatted

Allow do not format 'script' and 'style' tags if they are set in the "unformatted" property from the configuration object.
You'll need to save opt.unformatted and restore it after you're done. You might also put it closer to https://github.com/JoseGoncalves/js-beautify/blob/master/js/test/beautify-tests.js#L1790 , since those are also script tag tests. 

Other than that, looks good.