Allow auto refresh of webview

[ftiff]

Some MacAdmins parse the index.html to write dynamic information such as an IP Address Feature Request would be to automatically refresh the webview every x seconds

[cybertunnel]

Could be a preference key

[cybertunnel]

To use this feature, you will need to set the webRefreshRate to a Number type with a value greater or equal to 1. This setting is in seconds of delay between refreshes.