refactor client
Merge branch 'master' of github.com:hazelcast/hazelcast into client-refactor

Conflicts:
hazelcast-client/src/main/java/com/hazelcast/client/spi/impl/ClientClusterServiceImpl.java
hazelcast-client/src/main/java/com/hazelcast/client/txn/TransactionContextProxy.java
code cleanup
Merge pull request #1710 from gurbuzali/client-refactor

Client refactor