add the option to create raw files directly, skipping the eimage generation step

[jchiang87]

For Run2.0i production, we'd like to save the disk resources needed to persist the eimage files, even temporarily. Since it's possible to integrate the conversion to raw files in the main simulation code, we should enable that option for Run2.0i.

[cwwalter]

This change was made in the 2.0i development work. I will add a new issue to make the functionality more flexible.