Starting on homestead shows reload snackbar

[jacogr]

Starting on homestead immediately showed the "reload this page" snackbar.

• start from "(unknown)" chain
• don't show message when previous state indicates "(unknown)" (or is the same as current)
• create tests for the middleware & dispatch conditions

There is an additional issue - the long polling causes the new chain to only show up after some time (along with the message), needs an additional issue/PR.

[ngotchac]

One small comment regarding this PR : I think the snackbar should stick (as errors do) and only a click would close it. If you're not watching the UI, then you won't see the notification... One other solution would be to use the Browser Notification API.

Also, another comment : after switching network, you get notifications about new ETH or tokens in your account (since the balances were previously at 0). Might want to handle that in another PR/Issue

[jacogr]

Valid comment on the close timing, will align with errors.

The issue I mentioned and you did needs to be logged though, out of scope here.