How to avoid type name start-case?

Issue Description:

All definition names are automatically converted to start case. As the [swagger doc](https://swagger.io/specification/) said:

> All field names in the specification are case sensitive

Expected Behavior:
I would like an option to control whether the tool converts definition names to start case or not.

Additional Information:

Version: 13.0.3
Steps to Reproduce: I found this issue when generating codes from [libpod's api](https://storage.googleapis.com/libpod-master-releases/swagger-latest.yaml), in which have two definitions called `networkCreate` and `NetworkCreate`.
I believe adding this configurability would enhance the usability and flexibility of the tool. Thank you for considering this enhancement!