Merge pull request #5 from cubejs/cluster3

rebase
implement nanny protection to avoid run away workers
implement nanny protection to avoid run away workers, readme
+ just refactorings, reduce the require used upfront in master.js, as some only needed by master alone.
+ fix #run, mainly for testing smaller granualities which depends on cluster environment (caching, emitter, status etc.)
refactorings, documentations for index#listen
Merge pull request #38 from inexplicable/cluster3

Cluster3 nanny feature