Removed duplicated code from create_in/output.
Removed duplicated code from create_in/output.

Previously, there were two functions in Transformation, create_input and
create_output, which were identical except for the replacement of "in" with
"out". The identical code has been moved into a function called "create_xput",
which is now called by both create_input and create_output.

Added a helper function add_structure to TransformationXput to create, clean,
and save a new XputStructure.

cfe-lab/Kive,cfe-lab/Kive,cfe-lab/Kive,cfe-lab/Kive,cfe-lab/Kive