cluster: debug args.
add an opMissingSlices to object batch workflow. compute the probabilities instead of labels. remove comments. change default halo.
put prediction into try to be sure
Merge branch 'synapse_pipeline' of github.com:ilastik/ilastik into synapse_pipeline
Revert "put prediction into try to be sure"

This reverts commit 9a9ac1ba4fefb5b1c199db76425cbea3d427d302.
synapse_pipeline: Added some extra assertions for quicker debugging of bad inputs.
wippity wip.