Allow no-property schemas

[mattbishop]

I want to create a schema that validates an object has NO properties, like this:

class EmptyObjectSchema {
}
getJSONSchema(EmptyObjectSchema) <-- throws Error: No schema properties found on class.

[mattbishop]

It would generate this schema:

{
  "type": "object",
  "properties": {
  }
}

[wigy-opensource-developer]

Yeah. Maybe if that helps implementing this feature, getJSONSchema could get default options for properties, objects and arrays. Something like getJSONSchema(EmptyObjectSchema, {property: {required: true}})