message: Update: docs after `etherscan` async refactor
  Also `autoselect` since this method need to be refactored as well
diff: @@ -307,7 +307,7 @@ const providerDefaults = metamask();
  etherscan([ProviderArguments: Object])
  ```
  -This method returns an provider instance object, instantiated with the necessary prop fields.
  +This method returns a `Promise`, which after resolving, will return a provider instance object, instantiated with the necessary prop fields.
  Even though it will work out of the box, it is highly recommended that you pass in at least the `apiKey` key via the `walletArguments` object. A new token for the Etherscan API can be generated [here](https://etherscan.io/myapikey).
  @@ -318,7 +318,7 @@ The only two _(optional)_ props that this method will take are `network` and `ap
  ```js
  import { etherscan } from 'colony-wallet/providers';
  -const provider = etherscan({
  +const provider = await etherscan({
  network: 'homestead',
  apiKey: '<your-token-key>',
  });
  @@ -390,10 +390,12 @@ This is just a helper method that goes through a list of providers _(both genera
  By default it goes through the following provider list, in order: `[metamask, etherscan, infura, jsonRpc]`, so if this works for you, just call it directly without any arguments:
  +This, as all other methos is `async`, meaning it will return a `Promise` with the selected provider instance.
  +
  ```js
  import { autoselect } from 'colony-wallet/providers';
  -const provider = autoselect(); // This will return the first available, instantiated provider
  +const provider = await autoselect(); // This will return the first available, instantiated provider
  ```
  Because it takes both generator methods and already-instantiated providers you can mix and match them:
  @@ -406,8 +408,8 @@ const localFallback = jsonRpc({
  network: 'ropsten',
  });
  -const provider = autoselect([
  - () => metamask({ network: 'ropsten' }),
  +const provider = await autoselect([
  + async () => await metamask({ network: 'ropsten' }),
  localFallback,
  ]);
  ```
  