Fix #6770 setting a timeout when jetty has low resources to prevent hub from hanging.
Fix #6771 if a session times out and the browser was never started, it should still be cleaned up on the hub side.
BeforeRelease should then be a no-op and not throw.
Fix #6772 adding a configuration parameter to set the number of thread jetty uses.
Default = -1 = current behavior ( 255 thread from Jetty's default settings )
cleaning out tests after the latest refatoring for grid.