Add a script to check all sample org-mode documents with the compare program.

src/compare/diff.rs

@@ -57,7 +57,7 @@ impl DiffResult {
 
     pub fn is_bad(&self) -> bool {
         match self.status {
-            DiffStatus::Good => !self.has_bad_children(),
+            DiffStatus::Good => self.has_bad_children(),
             DiffStatus::Bad => true,
         }
     }