Add rspec color option
Update flash message default key matching

Most used flash keys are "notice" and "alert". They are used respectively
for notice messages, for example after a successful update, and for error
messages, for example after a validation error. These keys are also the
only usable as parameters with the `redirect_to` method, see
https://github.com/rails/rails/blob/master/actionpack/lib/action_controller/metal/flash.rb

That's why foundation's "alert" class is now associated with the standard
"alert" flash key instead of the non standard "failure" key.

Anyway now you can use a hash parameter to override default behavior with
custom key matching, see specs for more informations.
Add notice about support for rails 3.2 and ruby 1.9.3