Support binary upload endpoint

[guillemcanal]

Given the following API definition:

swagger: '2.0'
info:
  version: 1.0.0
  title: Demo API
host: httpbin.org
schemes:
  - https
consumes:
  - application/json
produces:
  - application/json
paths:
  /post:
    post:
      summary: Upload file
      operationId: uploadFile
      consumes:
        - application/octet-stream
      parameters:
        - name: file
          in: body
          schema:
            type: string
            format: file
      responses:
        201:
          description: lol

Then we SHOULD support a filename or a stream for any given body parameters having schema.format = file.