New Cocoa Bindings examples for PyObjC 1.3

A new PyObjC user has been going through the motions of translating several popular Objective-C Cocoa Bindings examples to PyObjC. Unfortunately, due to our lack of documentation and existing examples on the subject, he has been having a bit of trouble with it . Fortunately, the pyobjc-dev mailing list has come to the rescue to provide quick and accurate answers to his questions.

So far, he's put together three excellent examples and contributed them to us. They're already in svn trunk and will be part of PyObjC 1.3:

• CurrencyConvBinding

  A rewrite of CurrencyConverter using Cocoa Bindings.

  Originally from Introduction to Developing Cocoa Applications Using Bindings, converted to PyObjC by u.fiedler.

• ManualBindings

  A simple example that illustrates establishing bindings programmatically, including a number of options such as validation and an array operator, and indexed accessor methods. A custom model object implements custom validation method.

  Originally from Cocoa Bindings Examples and Hints, converted to PyObjC by u.fiedler.

• TemperatureTransformer

  An example that uses NSValueTransformer to convert between Celsius and Fahrenheit.

  Based on Apple's Value Transformers documentation, converted to PyObjC by u.fiedler.