Sync context with latest spec version.

- Switch `encodingFormat` term back to `mediaType`.
  - w3c/vc-data-model#1408
  - w3c/vc-data-model#1440
- Add `EnvelopedVerifiablePresentation`.
- Add type for `statusReference` and `statusSize`.
- Fix whitespace.

Author: davidlehn

contexts/credentials-v2.jsonld

@@ -71,12 +71,13 @@
       "@id": "https://w3id.org/security#digestMultibase",
       "@type": "https://w3id.org/security#multibase"
     },
-    "encodingFormat": {
+    "mediaType": {
       "@id": "https://schema.org/encodingFormat"
     },
     "description": "https://schema.org/description",
     "name": "https://schema.org/name",
     "EnvelopedVerifiableCredential": "https://www.w3.org/2018/credentials#EnvelopedVerifiableCredential",
+    "EnvelopedVerifiablePresentation": "https://www.w3.org/2018/credentials#EnvelopedVerifiablePresentation",
     "VerifiableCredential": {
       "@id": "https://www.w3.org/2018/credentials#VerifiableCredential",
       "@context": {
@@ -189,8 +190,14 @@
           "@type": "https://w3id.org/security#multibase"
         },
         "ttl": "https://www.w3.org/ns/credentials/status#ttl",
-        "statusReference": "https://www.w3.org/ns/credentials/status#statusReference",
-        "statusSize": "https://www.w3.org/ns/credentials/status#statusSize",
+        "statusReference": {
+          "@id": "https://www.w3.org/ns/credentials/status#statusReference",
+          "@type": "@id"
+        },
+        "statusSize": {
+          "@id": "https://www.w3.org/ns/credentials/status#statusSize",
+          "@type": "https://www.w3.org/2001/XMLSchema#positiveInteger"
+        },
         "statusMessage": {
           "@id": "https://www.w3.org/ns/credentials/status#statusMessage",
           "@context": {

js/context.js

@@ -84,7 +84,7 @@ export default
       "@type": "https://w3id.org/security#multibase"
     },
 
-    "encodingFormat": {
+    "mediaType": {
       "@id": "https://schema.org/encodingFormat"
     },
 
@@ -94,6 +94,9 @@ export default
     "EnvelopedVerifiableCredential":
       "https://www.w3.org/2018/credentials#EnvelopedVerifiableCredential",
 
+    "EnvelopedVerifiablePresentation":
+      "https://www.w3.org/2018/credentials#EnvelopedVerifiablePresentation",
+
     "VerifiableCredential": {
       "@id": "https://www.w3.org/2018/credentials#VerifiableCredential",
       "@context": {
@@ -163,6 +166,7 @@ export default
 
         "id": "@id",
         "type": "@type",
+
         "holder": {
           "@id": "https://www.w3.org/2018/credentials#holder",
           "@type": "@id"
@@ -219,8 +223,14 @@ export default
           "@type": "https://w3id.org/security#multibase"
         },
         "ttl": "https://www.w3.org/ns/credentials/status#ttl",
-        "statusReference": "https://www.w3.org/ns/credentials/status#statusReference",
-        "statusSize": "https://www.w3.org/ns/credentials/status#statusSize",
+        "statusReference": {
+          "@id": "https://www.w3.org/ns/credentials/status#statusReference",
+          "@type": "@id"
+        },
+        "statusSize": {
+          "@id": "https://www.w3.org/ns/credentials/status#statusSize",
+          "@type": "https://www.w3.org/2001/XMLSchema#positiveInteger"
+        },
         "statusMessage": {
           "@id": "https://www.w3.org/ns/credentials/status#statusMessage",
           "@context": {