ensure java enum used for enum parameters #273

[davidmoten]

• Fix for Enums in Path or Query Generated as Strings #273
• [Breaking change] Also fixes overly verbose auto-generated class names for enum or complex anonymous parameter types so that:

paths:
   /params:
      get:
      parameters:
        - name: first
          in: query
          type: string
          enum: [thing, other]

generates a type for the first parameter called ParamsGetFirst instead of ParamsGetFirstParameterFirst