gFlex version 0.7 (development)

This release may be short-lived, but is the turning point at which work on gFlex will go from fixing deficiencies to adding new capabilities. As such, it is receiving version 0.7 (the last version of its parent project, "Flexure", was 0.6 back in 2012). It now seems to be functional and stable, and thus this tagged release will be the basis for this stage of the model to be pulled to @csdms-contrib and @umn-earth-surface.