refactored I/O sources:
1. Added new getInputHandler for all modules
2. Refactored (simplified) existing getOutputHandler for all modules
3. Updated the AvroReading trait for consistency
simplified the prefix extraction
reorganization
fixed issue with prefix extraction
moved AvroReading trait into modules package
fixed issue with parsing URL instead of path
clean up
updated the documentation to reflect command/API changes
added a new Zookeeper connection command
updated commands to use Unix-style parameters