Uncaught TypeError: Cannot read property 'hs' of undefined

[jaseemabid]

First of all, thank you for the great library.

I've been noticing a lot of uncaught exceptions and I followed https://github.com/benkeen/d3pie/issues/48 to add a pie.destroy() before redraw.

Now, the following block of code throws the exception Uncaught TypeError: Cannot read property 'hs' of undefined during a redraw.

checkConflict: function(a, b, c, d) {
            var e, g;
            if (!(1 >= d)) {
                var h = a.outerLabelGroupData[b].hs;

[skarpyak]

Have same issue in a lot places, if i have data array[n], "index" can have values 0...2n, as result exception rised