Removing field coercion from FieldDescriptor.__set__
Adding value coercion to the validate function
Adjusting schematics.validate.validate to throw an exception on validation errors, similar to calling instance.validate
This commit fixes 15 broken tests.  5 more to go and 6 failures.
Migrated tests over to new exception throwing in validate
Fixed some tests by ensuring models are instantiated during __set__, which was lost from removing coercion from __set__
Moving required check to validate_required for consistency
Removed min_size setting required field. This is caught, instead, by a minimum length check so that error reporting is specific.
All tests are passing with __set__ no longer coercing values