Failing unittests (Windows) ignored
Header, cookie, and form parameters should be optional

According to the spec
(https://github.com/wordnik/swagger-spec/blob/master/versions/2.0.md#parameterObject),
only "path" parameters are required by default, while for
all other parameter types the default value is "false".
Implemented vendor-specific fields at Operation and Parameter level
Make response headers available to the code generator (tryout)