Added support for individual asset-file-options

Assets in $js and $css can now have individual options by using [$path, $options] instead of $path.

    public $js = [
            ['js/vendor/custom.modernizr.js', ['position'=>View::POS_HEAD]],  //new option
            'js/myscript.js',
            'js/mysecondscript.js'
    ];

    public $jsOptions = array(
        'position'=>View::POS_END
    );