Use caching in HBase scan
Add basic input and output counters
Add metrics-based counters for batch indexing

Handling of metrics-to-counter information will be easier with
a switch to codahale metrics 3.x, but that isn't an option at
the moment due to the changed handling of JMX reporting in the
3.x release.
Avoid issues with Jackson version in local Hadoop install

When using Jackson while starting up a MR job, we're dependent
on the version of Jackson that is included in Hadoop. This commit
changes a method call to a deprecated version so that we're
compatible with pre-1.9 versions of Jackson.
Minor formatting change in MapReduce metric names
Allow config overrides of HBase scanner caching
Removed "ForkedMapReduceIndexerTool" from tool help
Only show error message with option eval errors
Rework some internal comments
Remove file-specific logging information
Fix logging of reported reduce slot count
Handle missing indexer name if indexer zk supplied
Handle incorrect/invalid indexer name parameter
Remove obsolete reducer count calculation
Improve docs on start and end row params