Update /About to explain how to use a CSVW schema

[Stephen-Gates]

W3C says CSVLint passed the CSVW Validation tests.

CSVLint/about doesn't mention this type of schema.

Can I use the CSVW schema instead of JSON Table Schema?

Where can I validate my CSVW schema before I use it to validate my CSV?

[JeniT]

The gem that csvlint.io is based on (https://github.com/theodi/csvlint.rb) supports CSVW and while we've wrapped that into csvlint.io it's not integrated all the way through (eg error messages won't be good yet). Best to use the command line that comes with csvlint.rb for the time being.

[quadrophobiac]

Hi @Stephen-Gates - renamed this ticket, hope you don't mind.
I think it would help to update the about page to include the exact details of CSVw support active on the service.
Whatever updates to the docs should be attentive to which version of library the service is currently running - see #321 (comment)