Client cleanup; lots of javadoc
Improved testing/javadoc/argument-checking for the ClientService
Improved ClientService javadoc
Minor checkstyle fixes in CLientServiceProxy
ignored tests with missing features
end of life for ProblematicTest.class
Merge pull request #3790 from mesutcelik/problematicTestsAreGone

end of life for ProblematicTest.class
Merge pull request #3764 from pveentjer/cleanup/3.x/client-further-cleanup

Cleanup/3.x/client further cleanup
Pulled out HazelcastClientInstance

Fixes #3781

Also improved documentation and minor cleanups
Minor testing improvements
Minor doc typo fix
Added package info to com.hazelcast.client.impl
Some rebasing fun