Add simpler interface

[danmichaelo]

First, thanks for creating this library! I just wonder if you would consider a simpler interface? I feel like four lines of code is a bit much to achieve something this simple:

$config = new \IcyApril\Tail\Config($fileLocation);
$config->setLines(2);

$tail = new \IcyApril\Tail\Tail($config);
echo $tail->getTail();

While keeping the existing interface, what do you think about adding a simpler shortcut? Perhaps something like:

echo Tail::tail($fileLocation, 2);

? I could submit a PR, but would like to know what you think first.