Show error if started application crashes immediately after start #64
Description
A user suggested to show an error message if an application silently exits shortly after having been launched.
This requires some process management, forking off a child process and monitoring it for, say, 5 seconds. If it does crash in that time (as in "non-zero exit code"), we should notify the user that the app probably has crashed. Xfce for instance implements a similar method if applications were started from the launcher, at least UX wise (I'm not quite sure whether this isn't just using apport on Ubuntu).