Test that navigating to admin/pages/new works

This test reproduces #43

Conflicts:
	spec/features/config_spec.rb
Fix invalid form_for call when creating new page

form_for in rails 3 only takes 2 arguments. The model type is inferred
from the first argument.
Fix missing String#to_slug method

Rails 3 changed in the way lib/ is required. We now need to require this
file manually.
Make format parameter optional on reference route

In rails 3 optional url parameters must be wrapped in parentheses.