When MimeType is 'application/octet-stream' generates InputStream

When MimeType is 'application/octet-stream' generates InputStream parameter (which reads bytes[] as opposed to Reader which reads char[]).

Includes MediaTypeGeneratorTestCase which is a copy of GeneratorTestCase
but loads core/src/test/resources/org/raml/mediatype/application_octet-stream.yaml
instead and checks that the generated interface takes an InputStream
param.