Avoid redundant info bubbles

Don’t notify the user if the new order status is the old one.
Merge pull request #227 from apoloval/task/GuiImprovements

Some improvements on wizard step progress indicator
Merge pull request #228 from sortega/avoid_bubbles

Avoid redundant info bubbles
Move local app data dir fetching to an independent class

The local data dir path is needed for purposes other than user settings
persistence. It's useful to extract how the local app data dir is computed
into an independent object.
Introduce `peerAddresses` in `NetworkComponent`

It's not clear how the addresses of the initial nodes of bitcoin network are
obtained. It seems natural to be `NetworkComponent` the trait that provides
them using the cake pattern.
Simplify `PeerGroupComponent`

The current interface of `PeerGroupComponent` considers that the implementers
must use an `AbstractBlockChain` to create the peer group. That's an
implementation detail that should not be present in the trait.

This change replaces the interface of `PeerGroupComponent` by a one that
just retrieves the peer group however it's created. That leads to move
its implementation from `IntegrationTestNetworkComponent` to a new trait
`SimplePeerGroupComponent`.
Introduce `DefaultBitcoinComponents` trait

This trait provide a default implementation for `PeerGroupComponent` and
`BlockchainComponent`. It require to be mixed with a `NetworkComponent` and,
from network parameters and peer addresses, it's able to provide a default
blockchain and peer group.

This new trait replaces `SimplePeerGroupComponent` and
`MockBlockchainComponent`.
Introduce `WalletComponent` (and implement it in `DefaultBitcoinComponents`)

This component provides a `Wallet` instance. The default implementation
creates a new wallet and loads its contents from a user wallet file (if exists).
Make `BitcoinPeerActor` to use the wallet provided by `WalletComponent`

Instead of creating a new one. This allows the wallet to be loaded from user
wallet file from the default wallet component implementation.
Make app to create the wallet after setup wizard

And fill it with the newly created key pair.
Remove `PrivateKeysComponent`

As it is not used anymore and, if needed, it's superseded by `WalletComponent`.
Remove private key config from bitcoin settings

Since it is not used anymore as we have the user wallet instead.
Merge pull request #229 from apoloval/task/cf-32

Persist bitcoin wallet in file