PyDev update site aggregator.

Bundles the following PyDev update site(s):

Other mirrors that may be manually used are:

Note: The only files directly available in this page are:

compositeArtifacts.xml and compositeContent.xml

Other files should be fetched by Eclipse based on the information collected from those files.

To check that the mirror it's pointing to is there, it's possible to check for the content.jar/artifacts.jar in it (as it doesn't have an index.html).