ext/zip, initial documentation

Hello, Here is a first version of the Zip documentation. I covers mostly all new features. It passes "make test" and the generated pages seem to be correct, however I prefer to have a deeper review prior to commit. Philip? :) Please find the docbook docs here: http://blog.thepimp.net/misc/zip/zipxml.tgz and the results: http://blog.thepimp.net/misc/zip/html/ref.zip.html Thanks in advance, -- Pierre