Bugfix: Fix duplicate constant warnings

From the RC to the final release, RSpec changed their base formatter so that it
would include `rspec/core/formatters/console_codes`.  Due to this, and because
we were requiring it in fuubar as well, users were getting warning about the
fact that constants had already been defined.

Now we're just requiring `rspec/core/formatters/base_text_formatter` and
allowing it to require `console_codes` for us.

Issue URLs:
  * #69
  * #70
  * #72

Actions:
  References #69
  References #70
  References #72

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lib/fuubar.rb

@@ -1,6 +1,5 @@
 require 'rspec'
 require 'rspec/core/formatters/base_text_formatter'
-require 'rspec/core/formatters/console_codes'
 require 'ruby-progressbar'
 
 RSpec.configuration.add_setting :fuubar_progress_bar_options, :default => {}