Fix for OPENAM-5407, review CR-5777 - providing Java Policy Agent support for Tomcat 8

Fix for OPENAM-3209, review CR-4544 - add support for updating Tomcat v6 global.xml during custom install

Fix for OPENAM-2726, review CR-4530 - when installing on Tomcat 7, don't present updating the global.xml as an option

Rework distribution builds to have a separate version per agent rather than generating multiple ZIP's per agent group. Updated build timestamp format to match format used in old Ant script. Part of work for AME-2042.