rspec/rspec-core — pull request #915 by dchelimsky (2013-05-22 22:15:18+00:00)
Title: Deprecation formatter

Per convo in #912, print deprecations through a new `DeprecationFormatter`, and change the deprecation API to:

```ruby
RSpec.deprecate("thing to be deprecated", :replacement => "it's replacement")
RSpec.warn_deprecation("custom message that is arguably better than the message generated by RSpec.deprecate for a specific scenario")
```