Unexport constants from order-utils.

Directly grab the EIP712 constants from the `order-utils` package in `/contracts/coordinator/test/util/hash_utils`.
Update changelogs.

contracts/coordinator/CHANGELOG.json

@@ -6,7 +6,10 @@
                 "note": "Created Coordinator package"
             },
             {
-                "note": "Use mixed EIP712 domains for transactions and approvals."
+                "note": "Use mixed EIP712 domains for transactions and approvals"
+            },
+            {
+                "note": "Add `SignatureType.Invalid`"
             }
         ]
     }

contracts/coordinator/test/utils/hash_utils.ts

@@ -1,4 +1,5 @@
-import { constants, eip712Utils, transactionHashUtils } from '@0x/order-utils';
+import { eip712Utils, transactionHashUtils } from '@0x/order-utils';
+import { constants } from '@0x/order-utils/lib/src/constants';
 import { SignedZeroExTransaction } from '@0x/types';
 import { BigNumber, signTypedDataUtils } from '@0x/utils';
 import * as _ from 'lodash';

packages/order-utils/CHANGELOG.json

@@ -1,14 +1,11 @@
 [
     {
-      "version"  : "7.1.0",
-      "changes": [
-          {
-              "note": "Add Coordinator EIP712 constants"
-          },
-          {
-              "note": "Export constants"
-          }
-      ]
+        "version": "7.1.0",
+        "changes": [
+            {
+                "note": "Add Coordinator EIP712 constants"
+            }
+        ]
     },
     {
         "timestamp": 1551479279,

packages/order-utils/src/index.ts

@@ -73,5 +73,3 @@ export {
     FeeOrdersAndRemainingFeeAmount,
     OrdersAndRemainingFillAmount,
 } from './types';
-
-export { constants } from './constants';