Use QFontDatabase to check if a font is scalable.
Use QFontDatabase to check if a font is scalable.

The flag set in QFontEngine was not always correctly set, use
QFontDatabase instead which is slower but should always be correct.
We fallback to native font rendering when the font is not scalable.

Change-Id: Ie9a2397abd42890d0fb05bc2f9c46a60040296f2
Reviewed-by: Eskil Abrahamsen Blomfeldt <e4034124b095075783ce739a2d1c68c0d66fa1fd@digia.com>

matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative