Provides the API used in the content packaging.

The content providers construct the {@link IPackager} with proper chain of {@link IPackagingProcessor}. The packaging processors consult the packaging context to determine the execution paths.

Usage:

    	IContent content = xxx;
    	IPackager packager = (IPackager) content.getAdapter(IPackager.class);
    	PackagingContext context = new PackagingContext();
    	// sets the input
    	context.setInput(content);
    	// sets various options
    	context.setAttribute(PackagingAttribute.workingDir, new File("myworkingdir"));
    	...
    	// builds the package
    	packager.buildPackage(context, null);