[OGRE-135] Italic fonts rendered incorrectly about ogre HOT 2 CLOSED

to tackle this one should compare the Ogre loading code

to other "freetype texture atlas" samples, like e.g.
https://gist.github.com/baines/b0f9e4be04ba4e6f56cab82eef5008ff

here is what crystalspace is doing:
https://github.com/crystalspace/CS/blob/3029384a26f1f16d0fa7b05142c2d8aaf5102726/plugins/font/server/freefnt2/freefnt2.cpp#L390

from ogre.

the core issue here is that ogre tries to treat glyph advance and glyph width as one. This works fine as long as width < advance, but breaks otherwise. Notably this happens with italic fonts, which would have to be rendered with overlap.

To really fix this we would need to render with advance, but this will silently break code for existing OgreFont users.

from ogre.