stopping octave-forge support in octave 3.0.1 on mingw

[Tribo Laboy]

Dear Matsuoka-san

Thank you very much for your support of the octave-forge and octave
packages on cygwin and mingw. The resources that you provide are a
great help and I have used them more than once. As someone who knows
how stressful work at Japanese Universities can be, I am thankful for
the support that you have been providing until now, but I am also glad
that you are  taking a break for a while.

Take care and all the best,

TL