`not-` classes cannot be combined

Fiddle

Studying the documentation for responsive class logic and also from several use cases i had the assumption that classes are freely combinable. For example, in the fiddle the "Company Name" field will always be shown within tablet and mobile breakpoints by adding mobile tablet in the class attribute.

When using not-*, it turns out the functionality breaks when trying to combine them. As you can try out in the fiddle, removing one of the two on the "Description" class-Attribute will work as expected, using two or more not--classes makes the column behave as if all was set.

This behaviour is inline with my understanding what happens around this area - basically one cancels out the other:

https://github.com/DataTables/Responsive/blob/master/js/dataTables.responsive.js#L425

imho (as this is also a reversed logic) this could be changed to be subtractive, rather than adding all other breakpoints to the includeIn array.

Reproduce the combined not-* behavior in the linked JSFiddle, then inspect js/dataTables.responsive.js around line 425 where includeIn is assembled. Verify how multiple exclusions are handled and confirm that the completed change makes the Description column respond correctly when two or more not-* classes are combined.