Complete implementation of consistency fixer.

src/java/voldemort/utils/ConsistencyFix.java
- added Execute method that orchestrates all the threads
- switched pattern of thread execution:
  - one thread for reading bad keys file that submits to ...
  - a thread pool of workers that enqueues badkeys for the ...
  - one thread writing still bad keys
  - note: construct thread pool with a blocking queue
- switched to logging (rather than System.out/err)
- added Stats tracking
- moved methods that do complicated work (getting & repairing keys) out

src/java/voldemort/utils/ConsistencyFixWorker.java
- moved methods that do complicated work (getting & repairing keys) in

src/java/voldemort/utils/ConsistencyFixCLI.java
- added 'progress-bar' option
- got rid of 'verbose' option
- moved all thread orchestration to ConsistencyFix