don't fix number of tessellated points later on
let tessellatedNodes parameter indicate how many *additional* nodes should be inserted

* fixes test for "poly->size() > 2" in ViewportParamsTest::geoDataLinearRing(), but doesn't make whole case pass yet
GraticulePlugin: Use GeoGraphicsItems for rendering the grid
Allow for icons in icon style

* If an icon is set in icon style for a GeoPointGraphicsItem
  draw it at the point's position
Allow for settings a font in MarbleGraphicsItems
MeasureToolPlugin: Port to GeoGraphicsItems
GraticulePlugin: Set default grid alignment to Corner

* This setting lets the plugin behave more like it did before
  the port to GeoGraphicsItems
Add GeoTextGraphicsItem and GeoRectGraphicsItem
Add GeoPixmapGraphicsItem
WIP: Port APRS plugin to GeoGraphicsItems
factor out ScreenLayer from GeometryLayer
wip idis
always create a canvas image in texture mappers
GeoPainter::mapTexture()
const'ify
remove ViewportParams parameter from MarbleGraphicsItem::paintEvent()
const'ify changeViewport()
split GeoGraphicsItem::paint()
remove customPaint()
WIP: split LayerInterface::render() into paint() and setViewport()