Make multi-row "simple" footer work with responsive

[exteon]

I understand that, as per https://datatables.net/forums/discussion/63149/colspan-header-responsive-issue, "complex" headers/footers are not supported. However, a multi-row footer without colspan or rowspan would hardly qualify as "complex" and is actually quite common (i.e. I'm using to display 2 rows containing filtered totals and unfiltered totals for each column). The responsive plugin works oly for the first row of the footer, which is inconsistent anyway (either work for all, or for none, but I get different length rows).

[AllanJard]

Yes you are right, that isn't really complex. Support for that will fall out of the work for colspan / rowspan.