Splash screen with Progress Bar - OSX

[fpietrosanti]

Apaf should provide a splash screen functionality, that can be enabled by the developer, and used to provide a nice splash screen of the application at it's startup operations.

The splash screen functionality must be initially available on OSX.

An howto for the branding of Apaf application should be available explaining:

• Specification of image formats for OSX to be used for splash screen
• How to convert a standard image to that size for OSX

The splash screen may contain additional dynamic information on the application startup process, that the developer can feed with useful startup information.

[fpietrosanti]

Some notes on making splash screen on OSX with PyObjc:

• https://trac.assembla.com/pyraf/browser/branches/opus_2008_4_public_rc/lib/splash.py