Minimize or remove delay when selecting an account

[filippsen]

Environment/Browser

Lab 1.6.1

Summary

Changing accounts takes a few seconds to compute. It takes a few seconds before the selection is active.
Example:

1. In Select an Account menu, create New Account
2. Select the newly created account

This is due to timer set in 'accountSelector' which updates balance every 3 seconds.

Suggestions

Consider changing from timer-based update to refresh based on a trigger or event. That would probably demand it to be an "action" or equivalent instead.

If we go the "action" way, we would probably need to update in lot of instances (deploying contract, calling contract functions, etc...)