Adds wrapAttrs option

[plakak]

I could really use this functionality and I think it's a good idea to include it as a standard option for everyone to use.

P.S. Amazing work with this library. Lifesaver for me. Thanks!

[hftf]

I suppose I would use this wrapAttrs option if I could pass in an object of functions:

findAndReplaceDOMText(..., {
    find: /.../,
    wrap: 'mark',
    wrapAttrs: {
        'class': 'match',
        'data-index': function(portion, match) { return match.index; }
    },
    ...
}

But then again, I'm using a replace function anyway:

function replace(portion, match) {
    var html = '<mark class="match" data-index="' + match.index + '">' + 
                   portion.text +
               '</mark>';
    return htmlToElement(html);
}
function htmlToElement(html) {
    var template = document.createElement('template');
    template.innerHTML = html;
    return template.content.firstChild;
}