Share rv-token across all subdomains

@settinghead please review. I believe I nailed it this time. I wish I had a better solution for "localhost", but I can't think of any.
@olegrise would it make more sense to do this
```js
/^localhost([\:][0-9]+)?$/.test(baseDomain)
```

because both
```js
/^localhost([\:][0-9]+)?$/.test("localhost");
/^localhost([\:][0-9]+)?$/.test("localhost:8099");
```
yield ```true```?