Check data is valid according to foreignKeys descriptor

[pwalsh]

When validating data against a JSON Table Schema, there may be foreign keys to other files.

This will need to be implemented in a way that supports:

• Processing of a raw data source + a table schema
• Processing of a DataPackage

[rufuspollock]

Good point. I don't know if you plan this as near-term but I would reiterate from "client" perspective that, for our immediate purposes, we can really follow "KISS" - see the user story

[rufuspollock]

Note just seen #8 which clarifies this is out of scope ;-)

[pwalsh]

WONTFIX for now. This will come for free when we update GoodTables to use Tabulator and related, newer tools