Refactored Consistency Check
Changed Rebalancer --output-dir option to append numbers to each .xml file it outputs so that we have access to interim cluster configs.
Tweaked Rebalancer --output-dir again to better name interim metadata files for each batch.
Added more info to cluster dump to track which nodes host 'hot' partitions.
Merge branch 'persistency-check' of git://github.com/zhongjiewu/voldemort into persistency-check
Review and cleanup of consistency checker.

- added required argument for an output file name for bad keys
- changed Reporter to print out 'just the key' to the output file; it
  outputs more info at DEBUG level in general.
- removed 'quiet' option
- throw exceptions:
  - if # partitions differ across clusters
  - if replication factor is hinky
  - if isExpired encounters unknown type
- main catches exceptions and fails fast
- changed system.out debugging to logger.trace