removed dead private/static function transform_or_invert_point()

fixes warning about unused function.
Added newline at end of file, fixing warning.
Renamed variable that was shadowing another outer variable.

Renamed inner variable from 'i' to 'j'.
Fixed return value of copy_auxiliary_data_from_minc2_file() function.

The function's comments say "RETURNS : VIO_OK or VIO_ERROR" but it would sometimes return -1, which I'm assuming should be VIO_ERROR.

Fixes compiler warning about -1 not being one of the VIO_Status enum values.  Indeed, that enum has no negative values.

This could be dangerous if clients of the function are depending on sometimes getting -1 though.  On the other hand, the current situation is also dangerous if clients are depending on the docs being right!