Back ported a lot of changes made to the Koans directory.

Evidently, a lot of changes / pull requests were made to the koans
directory and not to the src directory.  Perhaps we should remove the
koans directory entirely from the repo.

src/about_true_and_false.rb

@@ -10,7 +10,7 @@ class AboutTrueAndFalse < EdgeCase::Koan
   end
 
   def test_true_is_treated_as_true
-    assert_equal __(:true_stuff), truth_value(true)    
+    assert_equal __(:true_stuff), truth_value(true)
   end
 
   def test_false_is_treated_as_false