added is_contest_complete function and updated teams.html printing of teams by adding conditionals

Author: spidey789

src/contestadmin/models.py

@@ -71,3 +71,11 @@ def get_participation(self):
             return self.FORMAT[self.participation - 1][1]
         else:
             return 'TBA'
+        
+
+    def is_contest_complete(self):
+        """
+        Returns true if contest is complete, false otherwise
+        """
+        
+        return self.results is not None