This commit is adding a new class QwtIndPlotMarker that will enable us
to indend Labels. The usage is pretty much the same,
please look at the changes in LTMPlot.cpp to see what will
change for using the new class.
So far the functionality is implemented for horizontally written labels only.
This solves the issue of all Labels (e.g. Seasons and events in LTMPlot case)
being on one line and thus being unreadable.
Signed-off-by: Simon Egli (Silzo) <smn.egli@gmail.com>
