Mark new wallet tx/utxo stores as dirty.

This change makes the disk syncer write all three files (wallet, tx,
and utxo) instead of just the wallet, which will result in warnings at
startup if the tx/utxo files cannot be found.

Fixes #30.

accountstore.go

@@ -201,6 +201,8 @@ func (store *AccountStore) CreateEncryptedWallet(name, desc string, passphrase [
 		name:   name,
 		dirty:  true,
 	}
+	account.UtxoStore.dirty = true
+	account.TxStore.dirty = true
 
 	// Save the account in the global account map.  The mutex is
 	// already held at this point, and will be unlocked when this