Make server compatible with scssphp 2.0.1

[jmroelofs]

In order to use server with scssphp 2.0.1 I had to add one line to omit the utf-bom (because that was placed after the "/* compiled by scssphp 2.0.1 on Mon, ...") and one line to set the importPaths (because that has to be implicitely set now).

My code is now:

<?php
require_once './vendor/autoload.php';

use ScssPhp\ScssPhp\Compiler;
use ScssPhp\ScssPhp\OutputStyle;
use ScssPhp\Server\Server;

$scssDirectory = 'scss';

$scssCompiler = new Compiler();
$scssCompiler->setCharset(false);
$scssCompiler->setOutputStyle(OutputStyle::COMPRESSED);
$scssCompiler->setImportPaths($scssDirectory);

new Server($scssDirectory, null, $scssCompiler)
    ->serve();

One could add defaults for those two in the __construct of Server.php to make it work nicely again with scssphp 2.0.1 and real easy to use.

I'm willing to make a pull request.