Qtogre : https://bugs.openmw.org/issues/1281

There are still 2 problems with this branch, and I would like to hear what you think.

1) on windows at least, you need OGreOverlay.lib . I don't know how to add this to opencs CMAke.

2) I don't exactly know what to do regarding resource groups and Ogre. Right now, Ogre is not aware of resources/OpenCS so I had to manualy place the font Comic.ttf in some other places. Besides, are the resource groups name fixed?  See PagedWorldSpaceWidget line 267...
This sort of initialization is dangerous. Let's be certain font gets null here, not elsewhere.