G2Script add_powder_histogram allways reads first bank when multi=False #372

When trying to import a single bank from a multi bank GSAS powder date file the add_powder_histogram function always imports the first bank regardless of what the databank parameter is set to, though uses the instrument parameters selected by the instbank parameter.

See the attached directory for a minimal example, you get bank 1 data but with the limits and instrument params of bank 2.

ExampleHRPD.zip