Possible improvement to submit tool using required field

[jaschil2]

Right now, there is a boolean field called 'required' in the info dict of most columns. It is currently unused and I'm not sure if all of them have it. We could finish adding the field to ever other column if necessary and leverage it to augment to validation process for submit. Right now all validations are done on a case by case basis as determined in the submit.py script as opposed to centrally determined from the database schema.