Merge pull request #2 from eklavya/akka-cluster-standalone-mode

Ui changes for leader and workers.
Realized it is important to self join a node in akka cluster before others can start joining it.
Made starting of UI and metrics system optional, as it is not required by default for atleast running tests
and thus can impact their speed of execution, to make them atleast marginally faster.
Fixed all tests suites.
Subscribe to only relevant event streams.
Each worker is aware of the current leader. Information can be used to show on the UI.
Default port for master or the first started worker is 7077 now. Which keeps it consistent with original behavior
Added support for tracking leader's web address
    and fixed a bug related to incorrect path to Worker.
Webui's bound port (Which can be different from requested port) to be updated on ui start.