merging of the xwidget branch to master

[joakim]

I think soon would be a good time to merge the xwidget branch to master.

While it isn't perfect, it will never be, and it's usable in practice
now I believe. We are also fairly early in the release cycle.

The feature is self contained, as well as I have been able to make it.

I've gotten a code review from Eli that I'm working through. I've
addressed the most serious issues, and the rest can continue in master.

So, now I would like to now what I must fix before merging, and what
work can reasonable continue in master.

-- 
Joakim Verona