* Make the monthly report going aroung 2 times faster by caching some parts of the domain tree
* Use getInventory API for search task lines, we still get objects in the zodb in order to
get properties like start_date and stop_date
* Use ERP5Report in order to have a report similar to other ones and ERP5 and make it
more appropriate for unit test

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@28178 20353a03-c40f-0410-a6d1-a30d3c3de9de