Added exception handling to part of the MultiProcessConsumer.
Added an is_alive() method to the consumer in order to faciliate graceful shutdowns.
Shortcut is_alive() check.
Added passthrough parameter and adjusted Consumer logic so that it can retrieve offsets even if autocommit is disabled.
Removed OffsetOutOfRangeError import.
Fixed should_fetch_offset passthrough.
Merge pull request #3 from Adapp/scott-branch-consumer-fixes

Added Error Handling and is_alive() Method