JSON schema update to validate keys in distribution array

[kvuppala]

Right now the schema doesn't validate the keys provided in the distribution array, it would be great to check if either of "accessURL" or "webService" is included in the array.

The data.json harvesters are also currently not taking the values from "webService" field in the distribution array, which is in works to address on harvesting side.

Opening the issue to track, will try to update the schema with right validation if we think it is good to address.

[philipashlock]

webService isn't currently defined as being part of the distribution array (or serving as an array either as per #261 and #224)

Validation to ensure that both format and accessURL are provided within the distribution array is part of pull request #286 which I think will be accepted soon

The issues with the data.json harvesters should be ticketed on the data.gov issue tracker.