Grid ID and Extra CSS use same prefix

[jonnygreen]

Is there a danger that the grid ID generated by https://github.com/troolee/gridstack.js/blob/master/src/gridstack.js#L411 could conflict with using <div class="grid-stack grid-stack-N">...</div> to specify a different grid width?

[troolee]

Yes, it could be a problem. Fixed.

Thank you