Capture application termination messages/output

Fix #139 

Next PR is cleaning up the host file created for dead containers which should be garbage collected. 
I thought we had discussed this, but not in the PR, I guess.

I expected this conversion to be done as part of the conversion from the versioned API (v1beta1/2/3) pod specification to the internal pod representation in pkg/api/v1beta[123]/conversion.go rather than as part of the conversion from manifest to boundpod. If a user creates a pod without specifying the path, I want subsequent GETs to show the default value.

However, if this otherwise works, I'm happy to merge it as is. Add a TODO here and a note to #1502 that this should be fixed. Then squash the commits.