Additional features in swagger-codegen, see https://github.com/swagger-api/swagger-codegen/pull/349

- string property with format uri and byte
- object property
- inheritance (see swagger.json)
- additional arguments (model/api package)
- some NPE eliminated

is needed for the improments in my pull requests for swagger-codegen

https://github.com/swagger-api/swagger-codegen/pull/349