Exit after changing workbench IP address to inaccessible.

[TechWizEric]

When changing the IP address of the Workbench from an IP-address that a physical client device is connected to (e.g. 192.168.1.113) to e.g. 127.0.0.1, at reload the client will exit with an error message. This regards Android devices, the same might apply for iOS devices but needs to be tested.

Steps to reproduce

1. Start the workbench. The server starts listening on the main network interface's address e.g. 192.168.1.113.
2. Connect to the workbench with ETC on a client device.
3. Load an app.
4. Connect to the Workbench from the machine running the Workbench using address 127.0.0.1:4042 (or localhost:4042). The Workbench server now listens to that address instead.
5. Reload the app.

Actual results
On Android devices An "Application Error" dialogue is displayed with the message "net::ERR_CONNECTION_REFUSED (http://127.0.0.1:4042/index.html)". At the press of its "ok" button the app exits.

Expected results
A user-friendly error message is displayed in the client that is unable to connect to the 127.0.0.1:4042 address. The app doesn't exit at the press of the dialog button, but rather goes back to its start page to allow for making a new connection.