CDAP-633 RunId of Currently Running Program 

Based on the discussion at
https://issues.cask.co/browse/CDAP-633

history endpoint is moved to /runs endpoint, with default call to runs will return all currently active and past runs of a program.

while /runs?status={completed/failed/active} can be used to filter the returned records.

This PR contains CLI command change and UI changes as well.
Makes sense to present the more simple states, but seems hacky to use strings here. Also, it looks like if a program is in the "STARTING" state, then it won't be visible via the /runs endpiont? I think we should make an enum for the internal states, and then an enum that groups some of those internal states together to simplify the API.