move AbstractNode to main package.

src/main/java/fucoin/AbstractNode.java

src/main/java/fucoin/actions/Action.java

src/main/java/fucoin/actions/join/ActionJoin.java

src/main/java/fucoin/actions/join/GeneralAction.java

src/main/java/fucoin/supervisor/SuperVisorImpl.java

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