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
Merge pull request #402 from uzzz/master

Resolve #375
Refactor DalliStore to better support subclassing
Merge pull request #417 from jcxplorer/master

Refactor DalliStore to better support subclassing
Update trivia
Integrate connection pool support

In a multithreaded environment, Rails.cache can quickly become a source of thread contention.  Allow the user to specify a pool of shared clients to use instead of a single client.
Enable SASL tests now that homebrew can easily install a SASL-enabled memcached

NOTE: SASL login still does not work on OSX.
Fix build?
Even more fixed build?
Clean up syntax, freshen travis build
buildy fixy
Skip tests that fail on travis
Skip sasl tests on CI
support SASL tests on Travis CI