Fix Autodisconnect On All Tabs Closed

Added an `autoDisconnect` boolean option to `Candy.init()` that defaults to `true` (the current behavior) that can be set to `false`.
Could I perhaps make a suggestion for clarity?

```
/** Boolean: disconnectWithoutTabs
 * Instructs Candy to disconnect from the server after closing the last tab. Defaults to `true`.
 * Set to `false` to remain connected even without any tabs open.
 */
disconnectWithoutTabs: true,
```