A new page has been created for viewing assets. This replaces the old
`selectedToken` state, which previously would augment the home page
to show token-specific information.
The new asset page shows the standard token overview as seen previously
on the home page, plus a history filtered to show just transactions
relevant to that token.
The actions that were available in the old token list menu have been
moved to a "Token Options" menu that mirrors the "Account Options"
menu.
The `selectedTokenAddress` state has been removed, as it is no longer
being used for anything.
`getMetaMetricState` has been renamed to `getBackgroundMetaMetricState`
because its sole purpose is extracting data from the background state
to send metrics from the background. It's not really a selector, but
it was convenient for it to use the same selectors the UI uses to
extract background data, so I left it there for now.
A new Redux store has been added to track state related to browser history.
The most recent "overview" page (i.e. the home page or the asset page) is
currently being tracked, so that actions taken from the asset page can return
the user back to the asset page when the action has finished.
The `TransactionViewBalance` component has been split into three
separate components. This was done primarily to make the asset page
easier to implement. Also the name `TransactionViewBalance` didn't
describe this component very well anymore.
Instead of the Ethereum and token-specific logic being in the same
component, the two cases were split into the `EthOverview` and
`TokenOverview` components respectively. They both use the
`WalletOverview` component, which has the structure shared by both
cases.
Brad Decker
Erik Marks
Mark Stacey