it starts once and then call himself until all sub trees are parsed.
- Increased from 100 to 1000 the number of objects in a bundle, this is
not that much because 1000 can be parsed in less than 20 seconds.
- Make Folder_reindexObjectList starts once and then call himself until
it finishes a list of lists of ids.
- make sure that ERP5Site_reindexAll still reindex objects in several modules by the
same time.
- Added additionnal_priority in order to increase default priority values, this
is very nice while doing hot reindexing.
- Added simple tag dependency in order to make sure the amount of reindexed objects
stay limited. Also decrease a lot the number of Folder_reindexObjectList activities
by the same time, like this performance is increased.
- Add a condition when adding after_tag parameter while calling Folder_riendexObjectList,
so we wait that the previous work was finished only after adding 1000 * nb_nodes
objects reindex activities.
- explain the most important points with comments

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@17070 20353a03-c40f-0410-a6d1-a30d3c3de9de