new: iterator interface and improved documentation for JKQTPDatastore
reorganization of library (better separation of common code in jkqtpcommon and other code e.g. in jkqtplotter or jkqtmathtext)
- improved documentation
- changed: using static const variables instead of \c #define for fixed default values (e.g. JKQTPImageTools::LUTSIZE, JKQTPImageTools::PALETTE_ICON_WIDTH, JKQTPlotterDrawinTools::ABS_MIN_LINEWIDTH, JKQTMathText::ABS_MIN_LINEWIDTH ...)
- new: added debugging option, which surrounds different regions with visible rectangles (JKQTBasePlotter::enableDebugShowRegionBoxes() )
- fixed: colorbars at top were positioned over the plot label
- new: frames (plot viewport, key/legend ...) may be rounded off at the corners
- new: diverse new styling options (default font name/size ...)
- speed improvements to JKQTMathText::useSTIX()
