- use slf4j (allow code reuse under Android, with slf4j-android)

pom.xml

ucoinj-core/pom.xml

...e/src/main/java/io/ucoin/client/core/UCoinClientCore.java

...c/main/java/io/ucoin/client/core/action/CommandLines.java

...ain/java/io/ucoin/client/core/action/CommunityAction.java

...src/main/java/io/ucoin/client/core/action/HelpAction.java

.../main/java/io/ucoin/client/core/action/IndexerAction.java

.../main/java/io/ucoin/client/core/config/Configuration.java

...java/io/ucoin/client/core/config/ConfigurationAction.java

...java/io/ucoin/client/core/config/ConfigurationOption.java

...va/io/ucoin/client/core/config/ConfigurationProvider.java

...ore/src/main/java/io/ucoin/client/core/model/Account.java

...c/main/java/io/ucoin/client/core/model/BasicIdentity.java

...main/java/io/ucoin/client/core/model/BlockchainBlock.java

.../java/io/ucoin/client/core/model/BlockchainParameter.java

...re/src/main/java/io/ucoin/client/core/model/Currency.java

...re/src/main/java/io/ucoin/client/core/model/Identity.java

...src/main/java/io/ucoin/client/core/model/LocalEntity.java

...core/src/main/java/io/ucoin/client/core/model/Member.java

...j-core/src/main/java/io/ucoin/client/core/model/Peer.java