Try to fix issue #1105. Until now if an UpdateComponentAction, a
LambdaAction, or any action that can contain those inside their
"else" or "then" action lists, resulted in a call to script.stop on
the script that contains them, the script would continue running,
because they didn't implement a stop() method. Basically only
the asynchronous ones did: DelayAction, WaitUntilAction and
ScriptWaitAction.
With this change num_running_ in Action replaces
DelayAction::num_running_ and WaitUntilAction::triggered_ to provide
the same is_running logic to other actions.
Andrew Zaborowski
da390d32f8