Add a synchronization stress test :
 The test creates a number of modification on the LDAP server and checks that the correct number
 of modify Messages are received by another thread that has subscribed to the changelog
 service using the changelogbroker API.
 
 It is possible to use several threads to create the modifications.

This test can take some time and is therefore tagegd as a slow test and will
only be run when the testall ant target is invoked.