Get route in selector

is it possible to have access to the clients route that called the table
to avoid sending extra information to the client

```js
new Tabular.Table({
name: 'My Cool Table',
stateSave: true,
collection: Submissions,
columns: [ ...
....
selector(userId) {
// HERE
}
```

Start at the Tabular.Table configuration and the selector(userId) entry point shown in the issue, then trace how the table request reaches the selector. Define how the calling route would be exposed without sending extra information to the client, and document the expected selector behavior before implementing or testing it.

Written by the indexing model from the issue text.