Octave rejected as a GSoC mentoring org

[Jordi Gutiérrez Hermoso]

Bit of bad news: Octave got rejected again as an independent mentoring
organisation for GSoC.

However, we can still participate under GNU as we did last year, so
GSoC isn't over for us! We should be working with GNU in order to get
as many student slots as we can.

Also, this year, we should work on keeping students. From the
beginning, we should emphasise that the goal is to become long-term
contributors to Octave.

- Jordi G. H.