Code cleanup and more work on DemoTransactionSigner
Tests have shown that when loading a wallet, there doesn't seem to be
anyone in the list of FollowingKeys and all the TransactionSigners are
null
There is a persistence problem with the list of transactionsigners ='(
when we reload the wallet there exists a DemoTransactionSigner but its
values are all empty.
I am about to revert from using <DeterministicKey>WatchingKey to
DeterministicKeychain in the HDWalletKit and DemoTransactionSigner
HDWalletKit is now back to passing around the ActiveKeychain of the
wallet instead of just the WatchingKey.