Log Message:
Update ruby-logging to 2.0.0.

== 2.0.0 / 2015-03-28

Enhancements
- added event filtering via the Filter framework
- improvements to buffered logging
- code readability improvements around meta-programming

Bug Fixes
- fixed an `already initialized error`
- avoid unnecessary mutex-ing in logger lookup

Deprecations
- dropped Ruby 1.8 support
- removed logger consolidation
- removed YAML style configuration
- removed the Logging::Stats module
- removed the Hash#getopt method
- removed the Growl appender
- moved the Email appender to the logging-email plugin gem