Merged in feature/mutable-metadata1 (pull request #221)

M1, M2 and M3 complete

* M1, M2 and M3 complete

* review changes

* docs

* docs

api/queryAPI/documents_test.go

@@ -113,12 +113,18 @@ func TestGetDocument(t *testing.T) {
 	err = cons.GetDocument(ctx, docId, queryapi.GetDocumentParams{})
 	require.NoError(t, err)
 	assert.Equal(t, http.StatusOK, rec.Code)
+	// Milestone 2.3a adds two new fields to DocumentEnriched. They are
+	// populated unconditionally (HasCustomMetadata as a *bool pointing to
+	// false when the document has no metadata; CustomSchemaId stays nil
+	// when no schema is bound).
+	falseVal := false
 	assertBody(t, rec, queryapi.DocumentEnriched{
-		Id:            docId,
-		ClientId:      "client_id",
-		Hash:          "hash",
-		HasTextRecord: false,
-		Labels:        []queryapi.LabelRecord{},
+		Id:                docId,
+		ClientId:          "client_id",
+		Hash:              "hash",
+		HasTextRecord:     false,
+		Labels:            []queryapi.LabelRecord{},
+		HasCustomMetadata: &falseVal,
 	})
 }