add oas3 examples

[dtkav]

Relates to #420
Split out examples from #621 to make code review easier.

Changes proposed in this pull request:

• move existing examples under examples/swagger2
• add more examples under examples/openapi

[coveralls]

Coverage remained the same at 99.553% when pulling f950ca6 on dtkav:oas3_examples into eb374a6 on zalando:dev-2.0.

[hjacobs]

Thanks!

[Ryan-Gordon]

Hey @dtkav , went to check out your PR as I was thinking of updating some of the examples to OAS3 also but found yours, when I try to run the projects I get this error :
swagger_spec_validator.common.SwaggerValidationError: 'swagger' is a required property
If the connexion library isn't fully ready for OAS3 that may be why but could you confirm if these run on your local machine ?

[dtkav]

hey @Ryan-Gordon - this PR was split out from #621 (add oas3 support) in order to make that PR smaller and more reviewable. We are working towards a 2.0 release of Connexion (that will include OpenAPI3 support) on the dev-2.0 branch. The idea is that we'll merge some backwards-incompatible changes, improvements, oas3 support, and then these examples.

[Ryan-Gordon]

Hey @dtkav,
Just checked out that other PR and can see quite a bit of work there so its all making alot more sense now. Thank you for clarifying !

[JuxhinDB]

Wonderful work, loved the examples!

[dtkav]

Thanks @JuxhinDB