Renamed constant.
Removed used import.
Renamed new sstable reducer.

 - This way we can still support the old reducer.
Store a reference to the ExecutorService.
Remove unused field.
Move column type into Aegisthus.

 - This is in preparation for making the reducer configurable.
Inline retrieval of inputFormatClass
Make reducer class configurable.
Renamed for consistency with other files.
Add back CassReducer from origin/master.
Fix negative partition numbers.
Move the columnar input classes to a new package

 - This will let us run the old and new code in parallel.
Restore old input files from master.
Added the pig column loader