drop maintainership.

I've just imported py-ipython for update of devel/accerciser, not interesting to
itself. Furthermore, pacaginf of py-ipython012 and py-ipython013 are not by me.
python25 is not in pkgsrc now.
Update ruby-spreadsheet to 0.9.1.

### 0.9.1 / 24.10.2013

Date:   Thu Oct 24 09:41:50 2013 +0300

* Add support for worksheet visibility
Updated math/ruby-spreadsheet to 0.9.1