`esl_sq_Copy` doesn't copy `tax_id` attribute

[valentynbez]

A tax_id attribute of sq object is not copied during esl_sq_Copy and -1 is automatically assigned as a value. https://github.com/EddyRivasLab/easel/blob/281c81377595ef781dff962d9572240406a5e364/esl_sq.c#L265-L352

[cryptogenomicon]

Yes, that's fine, because tax_id is unused right now... a placeholder for future development. There are various other places in the code that would have to be changed if/when we start using it.

[althonos]

Thanks for the confirmation @cryptogenomicon.