Ruby and Rspec versions

Maybe `.ruby-version` shouldn't be in the repo, but since it is, this is the version available on Heroku Cedar (they don't offer REE). Might be good to test with both, though we'd probably want the latest `ree-1.8.7-2012.02`.

Also bumped Rspec.

This looks like a useful transitional gem. Unfortunately the specs are failing for me:

```
load_missing_constant': uninitialized constant Rspec::Rails23::Controllers (NameError)`
from /Users/nathany/Development/Fava/rspec-rails23/spec/lib/rspec/rails23/configuration_spec.rb:20
```