* Add mozilla plugin key to manifest
* Move all chrome references into platform-checking module
Addresses #453
* Add chrome global back to linter blacklist
* Add tests
When starting up, we now create a `web3` inside the `background.js` process, which we pass to the `idStore` and ask for the current `network`.
We include the `network` on `app.metamask.network` in the state object.
We re-request the network when changing provider.
We filter the transaction list for transactions that match the current network.