Atmos version 2.1

• Added support for Scala 2.11 in addition to Scala 2.10.
• Added atmos.ResultClassifier, atmos.ResultClassification and modified the retry logic to support unacceptable
  results. Also added onResult, acceptResult, rejectResult and other supporting classes to the DSL.
• Changed backoff policies from accepting previousError: Throwable to outcome: Try[Any] in order to support the
  addition of result classifiers. This is a breaking change for any implementations of BackoffPolicy, as well as any
  uses of atmos.backoff.SelectedBackoff or the DSL method selectedBackoff. Uses of other backoff implementations
  or other backoff elements of the DSL will continue to compile normally.
• Changed event monitors from accepting thrown: Throwable to outcome: Try[Any] in order to support the addition of
  result classifiers. This is a breaking change for any implementations of EventMonitor or extensions of the
  classes defined in atmos.monitor. Direct usage of the DSL will continue to compile normally.
• Added support for chaining together multiple event monitors in atmos.events.ChainedEvents and in the DSL as
  alsoMonitorWith.
• Added library and DSL support for fine grained event monitoring to all supported event monitors.
• Added support for chaining together multiple result classifiers and error classifiers in the DSL.
• Moved from using the deprecated rummage.Timer to the new rummage.Clock for tracking time and implementing synchronous and asynchronous backoffs.
• Included the rummage.Deadlines DSL in the atmos DSL, enabling the use of withDeadline on arbitrary futures.