Implemented the possibility to notify an observer when a transaction is finished

...in/java/fucoin/actions/control/ActionWalletSendMoney.java

...transaction/ActionCommitDistributedCommittedTransfer.java

...transaction/ActionInvokeDistributedCommittedTransfer.java

...ava/fucoin/actions/transaction/ActionInvokeSentMoney.java

...java/fucoin/actions/transaction/ActionNotifyObserver.java

...tion/ActionPrepareDistributedCommittedTransferAnswer.java

...main/java/fucoin/configurations/DefaultConfiguration.java

...ucoin/supervisor/DistributedCommittedTransferRequest.java

src/main/java/fucoin/wallet/AbstractWallet.java

src/main/java/fucoin/wallet/WalletImpl.java