Remove sub field from the JWT payload (fixes #356 and #363)

Author: bvdh

docs/specification/1.0.md

@@ -506,7 +506,6 @@ The JWT payload contains the following fields:
 Field | Optionality | Type | Value
 ----- | ----- | ----- | --------
 iss | REQUIRED | *string* | The URI of the issuer of this JWT.  Note that the JWT may be self-issued by the EHR, or may be issued by a third-party identity provider.
-sub | REQUIRED | *string* | Client_id of the EHR.
 aud | REQUIRED | *string* or *array of string* | The CDS Service endpoint that is being called by the EHR. (See more details below).
 exp | REQUIRED | *number* | Expiration time integer for this authentication JWT, expressed in seconds since the "Epoch" (1970-01-01T00:00:00Z UTC).
 iat | REQUIRED | *number* | The time at which this JWT was issued, expressed in seconds since the "Epoch" (1970-01-01T00:00:00Z UTC).