Merge OpenOLAT default branch to OpenOLATpro default branch with 4e460d94d3ae48a401d3895e3490514abfdc0cb5
OO-834: delegate the search to a pool to contains the Lucene bag habit to use ThreadLocals, update Lucene to 4.5.1
OO-831: iterate through subscriptions with a page query, remove the 2 StringBuilder which collect the audit log