Incorporate rspec-core's project initialization.

The Rails centric helper is now `rails_helper`. Leverage the standard
RSpec configuration for creating basic configurations for `.rspec` and
`spec_helper`. This also keeps us in-sync with any future changes.

- Fix #1029
Remove duplicate settings between the helpers.

The `rails_helper` only needs to be concerned with rspec-rails specific
configurations. Any general configuration is handled by `spec_helper`.
Note change of `spec_helper` and `rails_helper`.
TEMP: To make specs happy until branch is merged.