Use allOf for all schemas in inheritance

[RicoSuter]

Closes #732

Tasks:

• Implement correct allOf behavior
• Check that code generators still work correctly
• Check dictionary inheritance schema generation

[RicoSuter]

Dictionary inheritance handling (Foo = container class)

        public class Foo
        {
            public Bar Bar { get; set; }
        }

        public class Bar : Dictionary<string, string>
        {
            public string Baz { get; set; }
        }

Schema (OpenAPI 3 style)

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "Foo",
  "type": "object",
  "additionalProperties": false,
  "properties": {
    "Bar": {
      "x-nullable": true,
      "oneOf": [
        {
          "$ref": "#/definitions/Bar"
        }
      ]
    }
  },
  "definitions": {
    "Bar": {
      "allOf": [
        {
          "type": "object",
          "additionalProperties": {
            "type": "string"
          }
        },
        {
          "type": "object",
          "additionalProperties": false,
          "properties": {
            "Baz": {
              "type": "string"
            }
          }
        }
      ]
    }
  }
}

Rules:

• First schema with no reference and object type is base schema. Correct?

[RicoSuter]

Question: In the sample above, how can i decide which one of the schemes in allOf is the base schema (i.e. inherited) when both are inline (no schema is referenced)? When one schema is referenced and one is inline, then the referenced one is the base schema...

Also see my dictionary test in the previous comment...

@darrelmiller Is the generated schema above correct for the given C# code? Can you answer the question in this comment (is there even an answer)?

[RicoSuter]

For reference, there is also oneof inheritance:
#13

[bakashinji]

As far as I can see the allOf Part looks correct. I haven't used the oneOf property as of yet, but in this case it seems unnecessary to me.

[RicoSuter]

Had to revert, because there are still some issues: New PR: #783