[ready to be merged] health webpage

Closes #56

CHANGES:
* Get frontend health, escluster info in cron jobs
* Write info to mongo in a cron job
* Display more info in the webpage (es and frontend)
* clean up the es stats system, Closes #75 by injecting stats in healhToMongo.py 
* have node info for es (OS CPU%, load avg, JVM mem %)
* hot threads logs for ES

Note: No need to refresh the page in the browser to see new data as it gets updated

[screenshot](http://imgur.com/wmeOviu)