Exposes a method (similar to routing specs) to set the routes in controller specs
Documentation updates

[ci skip]
Documents how to use the new `routes` DSL with controller specs
Do not raise an error if `bin/rails` was already removed
Reliably skip cucumber features only on Rails 3.0
Bumps to 2.13.1
Rely on ::Rails::VERSION::STRING instead of an overly complex module

* I did not know about ::Rails::VERSION::STRING until recently. It seems
  to be defined all the way back to 3.0.0, which is all we need.