Qwt 5.0.0 Release Candidate 1

Changes since Release Candidate 0:

1) Flickering of QwtMagnifier in combination with QwtPlot::autoReplot(true)
fixed.
2) QwtPlotSVGItem 4.2.0 updates.
3) QwtLegend::LegendDisplayPolicy, QwtSymbol::Style, QwtSlider::ScalePos,
QwtThermo::ScalePos changed to avoid conflicts with X11 headers.
4) QwtPicker::rubberBandWidget/trackerWidget getters added.
5) MinGW/Qt3 fixes.
6) Memory leak fixed ( important when QwtPlot::replot is called very often).
7) Workaraound for a xlC 5.1 compiler bug added.
8) QwtPanner: cursor handling fixed.
9) QwtPlotCanvas(Qt3 only): background painting fixed for uncached painting.
10) QwtPlotLayout: bug in AlignCanvasToScales mode fixed.
11) Plugin for the MathML renderer of the Qt solutions package completed.