[Rails] rspec-expectations-2.9.1 is released!

rspec-expectations-2.9.1 is released!

This is a bug-fix only release, and is recommended for everybody using rspec-2.9.

### rspec-expectations-2.9.1 / 2012-04-03
[full changelog](http://github.com/rspec/rspec-expectations/compare/v2.9.0...2.9.1)

Bug fixes

* Provide a helpful message if the diff between two objects is empty.
* Fix bug diffing single strings with multiline strings.
* Fix for error with using custom matchers inside other custom matchers
 (mirasrael)
* Fix using execution context methods in nested DSL matchers (mirasrael)