Support The Menubar In Ubuntu 12.04+

I request Renoise support Ubuntu’s MenuBar; technical docs (and code-ish stuff) here:

From a user’s point of view, ie. me who used to be on OS X, it’s the same deal as on OS X: Use the cleaner, always present, integrated menus when not full-screen.

Thank you for your consideration.

Renoise uses that on OSX??