[daisy] 'read live' permission

[Bruno Dumon]

I have implemented a new 'read live' permission for use in the ACL. To
summarize, we now have the following permissions:

read live
read
write
publish
delete

The 'read live' permission is the most restrictive permission of these.
It allows read access, but only to live version of the document (and to
non-versioned data of the document), and this only for non-retired
documents.

This sort of access limitation becomes important if we want to support
public sites where you don't want users to be able to access older and
newer versions by manipulating the URLs. To a certain extent it would be
possible to disallow this in the frontend, but having a 'read live'
permission on the repository level makes this ubiquitous. For example,
query results will then also be filtered.

-- 
Bruno Dumon                             http://outerthought.org/
Outerthought - Open Source, Java & XML Competence Support Center
bruno at outerthought.org                          bruno at apache.org