add mime-types

[TomCJones]

it might be inferred that it is application-jose, but i think it would be better to call it out

[TomCJones]

here is a comment from jim fenton, which i do not agree with, but want him to be heard;
From jimfenton to Everyone: 02:53 PM
Unfortunately application.jose doesn’t do quite what I was referring to, because it points to RFC 7515 (JWS). We need a way to specify parts that are plain text, images, HTML, …
From jimfenton to Everyone: 02:58 PM
No, not at the http level…I’m talking about the content of the body element.
From Me to Everyone: 03:01 PM
I agree with that part of Jims comment so long as i do not have to use mime-types internally

[tplooker]

To be clear what this issue is asking for is defining the mime-type used by the transport layer responsible for sending the JWM? As opposed to the internal mime-type that may be included in a JWM to describe some of the embedded content?