Improve logger documentation.
Warn if Consumer is naively configured in a way that will cause busy-looping
Revise message re: code review
Update docs to reflect actual behaviour of MaxWaitTime=0
Use sarama.Logger.Println rather than log.Println
Move config check to matched check for consistency
Phrasing/syntax tweaks.

Also make the warning message point to the documentation.
Merge pull request #42 from Shopify/warn_on_poor_configuration

Warn if Consumer is naively configured in a way that will cause busy-looping
Get rid of a magic value of the compression codec mask
Merge pull request #44 from Shopify/compression_mask_magic

Get rid of a magic value of the compression codec mask
When compressing messages, wrap them in a message-set
Compression codec is only two bits, not three.

As per discussion on https://issues.apache.org/jira/browse/KAFKA-1110
Merge pull request #45 from Shopify/compress_message_sets

When compressing messages, wrap them in a message-set
Merge pull request #46 from Shopify/change_compression_mask

Compression codec is only two bits, not three.
Add PanicHandler
Merge pull request #50 from Shopify/panic_handler

Add PanicHandler to ClientConfig
Fix panic handler bug (#52)
Merge pull request #53 from Shopify/panic_handler_race_condition

Fix panic handler bug (#52)