add a note about new compressors. closes #406
Merge pull request #407 from pitr/patch-1

add a note about new compressors. closes #406
less encryptic error message when version is < 1.4

@error and @msg are both nil, thus the message says it's down
even though you've verified it is definitely up...something is lying!
Then you read the docs.
Merge pull request #414 from shaiguitar/master

less encryptic error message when version is < 1.4
Add better support for safe updates with multiple writers
Merge pull request #398 from philipmw/get-set-with-cas

Add get-with-cas ('gets') / set-with-CAS functionality
Cleanup
Trim helper junk from the public API
Fix bug with get key with "Not found" value