On browser refresh you get 2 api calls - Router issue

[martinbryant]

Description

When the app first loads/browser is refreshed on any page that requires data, you will see that a duplicate call to the server is made when looking at the Network tab in the browser dev tools

Expected behaviour

Only 1 api call is made

Actual behaviour

2 api calls are made

Related information

I have narrowed it down to the UrlChanged msg in Index.fs is being called on first load/browser refresh which is causing the call to be made twice. Pre SAFE v5 this did not happen.