Starting the same application twice should return an error

[stefanoborini]

Right now if you use the remoteapprest script to start an application that is already running is basically a no-op. We should return an error instead.

[stefanoborini]

After investigation, it's not technically a no-op. What happens is that the container manager, when asked to start a container that is already there, stops the old one and starts a new one. It is debatable if this is appropriate behavior.