Enable set font size to JKQTMathText in pixels.

[igormironchik]

Hello. The subject.

Corresponding to the code:

class JKQTMATHTEXT_LIB_EXPORT JKQTMathText : public QObject {
    protected:
        /** \brief base font size in points */
        double fontSize;

Font size in JKQTMathText is set with points, that is platform dependent, as Qt for a long time is not accurate in this question. I did a lot of applications where were necessary to see the same picture on all devices, and I was forced to calculate fonts' sizes by hands and set them in pixels.

Thanks.

[jkriege2]

implemented in 2ef1813 ... hope it works for you