Fix idle patients after using the drinks machine

After beta3 patients began to idle before the drinks machine again.
This is caused by the idle action that is inserted by the drinks
machines after_use function. The change skips inserting the idle
action into the action queue, if the patient already left the queue.
Add workaround for standing patients that fell of a queue

The workaround for patients that fell off a queue only caught patients
sitting on a bench. It now checks and fixes standing patients, too
Merge pull request #415 from phillipp/standing-patients-queue-fix

Standing patients queue fix