[Qgis-developer] install instructions

[Matthias Kuhn]

Hi,


>
> I had actually been wondering if we should make a small deb that users
> can double click that does the setup of the repos for them (creates the
> source.list.d/qgis.list). Would even be awesome to make it detect the
> version of the OS and put in the right repos for that version. Then we
> could move the how to do it by hand to an Advanced section.

I would also appreciate a one-click solution. But I would make a shell 
script instead of a .deb, so it will work across different 
distributions.

Matthias