Formats like LaTeX could have never been exported because
`setattr(cls, set_%s % fmt.title, fmt.import_set)` always failed
for export-only formats and with that the exception was caught in the
outer try/except and the format tuple was set to (None, None) with
`cls._formats[fmt.title] = (None, None)`

Error: frzn_col_idx not defined

As in #53 already solved. Freeze panes set to A2 again.