Fix #426 - Problem with boolean fields in list view

Guesser/TypeGuesser.php

@@ -67,7 +67,7 @@ class TypeGuesser implements TypeGuesserInterface
             //case 'array':
             //  return new TypeGuess('Collection', array(), Guess::HIGH_CONFIDENCE);
             case 'boolean':
-                return new TypeGuess('checkbox', array(), Guess::HIGH_CONFIDENCE);
+                return new TypeGuess('boolean', array(), Guess::HIGH_CONFIDENCE);
             case 'datetime':
             case 'vardatetime':
             case 'datetimetz':