ISIS-529: hidden versions of setting services.
ISIS-530: upgrades to wicket 6.10.0
ISIS-531: reinstating metamodel "API" classes.
ISIS-533: keep flushing until no more commands to flush
ISIS-535: application-specific logging example

executing the ToDoItem#updateCost action will log to Stderr (debug level)
ISIS-536: thread local as a means of temporarily disabling concurrency checking.
Merge remote-tracking branch 'upstream/master'