Handle multiple tbodies where no thead is before the tbody.

[kyle-wannacott]

https://github.com/LeeWannacott/table-sort-js/pull/110 Now we have multiple tbodies being sorted that have thead before tbody, we need to handle if no thead exists, or worse the thead is inside the tbody : /

[kyle-wannacott]

technically having multiple theads in a table is illegal html, Even though it seems to work? Should probably implement this in that we check the first row of subsequent tbodies to see if they have th and if so make clickable.