Fix PySpark unit tests on Python 2.6.
Updated json output to allow for display of worker state

Ops teams need to ensure that the cluster is functional and performant.  Having to scrape the html source for worker state won't work reliably, and will be slow.  By exposing the state in the json output, ops teams are able to ensure a fully functional environment by querying for the json output and parsing for dead nodes.
Rename `memoryBytesToString` and `memoryMegabytesToString`

These are used all over the place now and they are not specific to memory at all.

memoryBytesToString --> bytesToString
memoryMegabytesToString --> megabytesToString
Merge pull request #829 from JoshRosen/pyspark-unit-tests-python-2.6

Fix PySpark unit tests on Python 2.6
Merge pull request #836 from pwendell/rename

Rename `memoryBytesToString` and `memoryMegabytesToString`
Merge pull request #834 from Daemoen/master

Updated json output to allow for display of worker state
Revert "Merge pull request #834 from Daemoen/master"

This reverts commit 230ab2722ebd399afcf64c1a131f4929f602177d, reversing
changes made to 659553b21ddd7504889ce113a816c1db4a73f167.
Use the JSON formatter from Scala library and removed dependency on lift-json.

It made the JSON creation slightly more complicated, but reduces one external dependency. The scala library also properly escape "/" (which lift-json doesn't).
fixing typo
Merge pull request #843 from Reinvigorate/bug-879

fixing typo in conf/slaves
Merge pull request #841 from rxin/json

Use the JSON formatter from Scala library and removed dependency on lift-json.