Fix: definition with inner schema and anonymous schemas

[tehcyx]

Hi,

We, a team from SAP working on API Hub and YaaS, started using this converter to convert our RAML definitions into Swagger. We found that some of our RAML files were failing to convert so we had to make some changes, and we wanted to share these changes with you. We collected the list of changes we made in this CHANGELOG and will provide each fix as a different pull request for you so that you can pick the ones that you want to support.

The issue to fix

1. A schema within definitions that is declared with $schema will break conversion
2. Schemas that don't have a title will override other (anonymous) schemas without a title

The fix

1. Will delete an inner schema from definitions and reference to it instead.
2. Introduce a sequence number to name anonymous schemas and make them reference-able. User should be able to spot and change definitions of these anonymous schemas with them having a stand-out name now.

Best regards,
Daniel Roth - SAP Hybris