KLBACKLOG-2267: more session tests from jetty
KLBACKLOG-2267: added cache for sessions to get HttpSessionEvent on session timeout
KLBACKLOG-2267: log info
KLBACKLOG-2267: if delete fails, check if already removed
merge jetty8
Merge branch 'KLBACKLOG-2267' into jetty8

* KLBACKLOG-2267:
  merge jetty8
  KLBACKLOG-2267: if delete fails, check if already removed
  KLBACKLOG-2267: log info
  KLBACKLOG-2267: added cache for sessions to get HttpSessionEvent on session timeout
  KLBACKLOG-2267: more session tests from jetty