[vtkusers] Parse code from QVTKWidget to QVTKWidget2

[Ben Boeckel]

On Tue, Dec 22, 2015 at 12:23:31 -0200, Lays Rodrigues wrote:
> Weel after add that variable to CmakeLists, the build runs without error.
> However when I try to run the app, this errors appears and the program
> crash:
> http://pastebin.com/YZXMDDNH

Hmm. Seems that there's some issue with the way the OpenGL context is
set up? Anyone with more knowledge about this have an idea?

--Ben