Function arrayify

stack/presentation/lib/impress.js:61–63

( a )

    // `arrayify` takes an array-like object and turns it into real Array
    // to make all the Array.prototype goodness available.
    var arrayify = function( a ) {
        return [].slice.call( a );
    };

    // `css` function applies the styles given in `props` object to the element
    // given as `el`. It runs all property names through `pfx` function to make