Unify rspec configuration

Author: pitr-ch

.rspec

@@ -1,2 +1,4 @@
 --require spec_helper
---format progress
+--color
+--backtrace
+--format documentation

Rakefile

@@ -149,9 +149,7 @@ begin
   require 'rspec'
   require 'rspec/core/rake_task'
 
-  RSpec::Core::RakeTask.new(:spec) do |t|
-    t.rspec_opts = '--color --backtrace --format documentation'
-  end
+  RSpec::Core::RakeTask.new(:spec)
 
   task :default => [:clean, :compile, :spec]
 rescue LoadError