added custom field-record validator support, not using it yet though

model.py

@@ -33,6 +33,13 @@ class Model(object):
         for f in self.get_fields():
             f.validate()
 
+            try:
+                custom_validator = getattr(self, 'validate_' + f.name)
+            except AttributeError, e:
+                continue
+            if callable(custom_validator):
+                 custom_validator(f)
+
     def output(self):
         return ''.join([self.record_identifier] + [field.get_data() for field in self.get_sorted_fields()])