added json encoder and partially functioning json decoder

pyaccuwage/fields.py

@@ -49,6 +49,19 @@ class Field(object):
     def parse(self, s):
         self.value = s.strip()
 
+    def toJSON(self):
+        data = self.get_data()
+
+        return {
+            '__class__': self.__class__.__name__,
+            'name': self.name,
+            'maxLength': self.max_length,
+            'required': self.required,
+            'data': data,
+            'value': self._value,
+            'dataLength': len(data)
+        }
+
 
 class TextField(Field):
     def validate(self):
@@ -146,6 +159,9 @@ class BooleanField(Field):
 
 
 class MoneyField(Field):
+    def __init__(self, name=None, max_length=0, required=False):
+        super(MoneyField, self).__init__(name=name, uppercase=False, max_length=max_length, required=required)
+
     def validate(self):
         if self.value == None and self.required:
             raise ValidationError("value required", field=self)