Fix a couple bugs in the JSON schema.

json_reporter.schema.json

 {
   "$schema": "http://json-schema.org/draft-04/schema#",
   "description": "An event emitted by the test package's JSON reporter",
 
   "definitions": {
     "Test": {
-      "required": ["id", "name", "metadata"],
+      "required": ["id", "name", "groupIDs", "metadata"],
       "properties": {
         "id": {"type": "integer", "minimum": 0},
         "name": {"type": "string"},
+        "groupIDs": {
+          "type": "array",
+          "items": {"type": "integer", "minimum": 0}
+        },
         "metadata": {"$ref": "#/definitions/Metadata"}
       }
     },
 
     "Group": {
       "required": ["id", "name"],
       "properties": {
         "id": {"type": "integer", "minimum": 0},
         "parentID": {
           "oneOf": [{"type": "integer", "minimum": 0}, {"type": "null"}]
@@ skipping 21 matching lines @@
     "time": {"type": "integer", "minimum": 0},
     "type": {"type": "string"}
   },
 
   "oneOf": [
     {
       "title": "StartEvent",
       "required": ["protocolVersion", "runnerVersion"],
       "properties": {
         "type": {"enum": ["start"]},
-        "protocolVersion": {"type": "string"},
+        "protocolVersion": {"type": "string", "pattern": "^0\.1\."},
         "runnerVersion": {
           "oneOf": [{"type": "string"}, {"type": "null"}]
         }
       }
     },
 
     {
       "title": "TestStartEvent",
       "required": ["test"],
       "properties": {
         "type": {"enum": ["testStart"]},
         "test": {"$ref": "#/definitions/Test"}
       }
     },
 
     {
       "title": "GroupEvent",
       "required": ["group"],
       "properties": {
         "type": {"enum": ["group"]},
         "group": {"$ref": "#/definitions/Group"}
       }
     },
 
     {
       "title": "PrintEvent",
-      "required": ["message"],
+      "required": ["testID", "message"],
       "properties": {
         "type": {"enum": ["print"]},
+        "testID": {"type": "integer", "minimum": 0},
         "message": {"type": "string"}
       }
     },
 
     {
       "title": "ErrorEvent",
       "required": ["testID", "error", "stackTrace", "isFailure"],
       "properties": {
         "type": {"enum": ["error"]},
         "testID": {"type": "integer", "minimum": 0},
@@ skipping 18 matching lines @@
       "title": "DoneEvent",
       "required": ["success"],
       "properties": {
         "type": {"enum": ["done"]},
         "success": {"type": "boolean"}
       }
     },
 
     {
       "title": "FutureEvent",
+      "description":
+        "A placeholder event to allow new events to be added in the future.",
       "properties": {
         "type": {
           "not": {
             "enum": [
               "start", "testStart", "group", "print", "error", "testDone", "done"
             ]
           }
         }
       }
     }
   ]
 }