CFileHelper::removeDirectory() Does not always delete the directory!

[CyberPunkCodes]

The current code does not always delete a directory recursively. In some cases, it deletes just the files. I am not sure exactly why, but I had a folder that this was failing to delete. After a little searching, I came across a nice, simple, elegant function that is pretty solid.

public static function removeDirectory($dir)
{
    $files = array_diff(scandir($dir), array('.','..'));
    foreach ($files as $file) {
        (is_dir("$dir/$file")) ? self::removeDirectory("$dir/$file") : unlink("$dir/$file");
    }
    return rmdir($dir);
}

I do not take credit for it, it was posted as a comment on php.net's docs: http://php.net/manual/en/function.rmdir.php named as delTree().

I purpose that we see if we can get some opinions on this, and possibly replace the current removeDirectory() function with this one.

[CyberPunkCodes]

@cebe A pull request has been created here: #3690