Typo in js/table_sort.js

[mymatenige]

There is a typo on js/table_sort.js.

this.callback_presort(table_id, heder_index);

should be

this.callback_presort(table_id, header_index);

I haven't spent time working out what this does, and whether the fix breaks something. But it's clearly a mistake.

Easy fix created in pull request #49.