Fix documentation issue where unsubscribeAll shown as method on every contractWrapper instance even though it's only used by Exchange and Token wrappers.

packages/0x.js/src/contract_wrappers/contract_wrapper.ts

@@ -50,10 +50,7 @@ export class ContractWrapper {
         this._onLogAddedSubscriptionToken = undefined;
         this._onLogRemovedSubscriptionToken = undefined;
     }
-    /**
-     * Cancels all existing subscriptions
-     */
-    public unsubscribeAll(): void {
+    protected unsubscribeAll(): void {
         const filterTokens = _.keys(this._filterCallbacks);
         _.each(filterTokens, filterToken => {
             this._unsubscribe(filterToken);

packages/0x.js/src/contract_wrappers/exchange_wrapper.ts

@@ -607,6 +607,12 @@ export class ExchangeWrapper extends ContractWrapper {
     public unsubscribe(subscriptionToken: string): void {
         this._unsubscribe(subscriptionToken);
     }
+    /**
+     * Cancels all existing subscriptions
+     */
+    public unsubscribeAll(): void {
+        super.unsubscribeAll();
+    }
     /**
      * Gets historical logs without creating a subscription
      * @param   eventName           The exchange contract event you would like to subscribe to.

packages/0x.js/src/contract_wrappers/token_wrapper.ts

@@ -281,6 +281,12 @@ export class TokenWrapper extends ContractWrapper {
     public unsubscribe(subscriptionToken: string): void {
         this._unsubscribe(subscriptionToken);
     }
+    /**
+     * Cancels all existing subscriptions
+     */
+    public unsubscribeAll(): void {
+        super.unsubscribeAll();
+    }
     /**
      * Gets historical logs without creating a subscription
      * @param   tokenAddress        An address of the token that emmited the logs.