implement UTM formatting in GeoDataCoordinates::*toString()
fix regression introduced in commit ad5d1579bac56def0eb5846a2a683a0628f7a02e

* texture of planet didn't rotate with globe when whole planet was visible
factor out ScreenLayer from GeometryLayer
wip idis
GeoGraphicsScene
always create a canvas image in texture mappers
GeoPainter::mapTexture()
const'ify
remove ViewportParams parameter from MarbleGraphicsItem::paintEvent()
const'ify changeViewport()
const'ify GeoGraphicsItem::paint()
remove customPaint()
WIP: split LayerInterface::render() into paint() and setViewport()
Merge latest code changes from shentok
GraticulePlugin: Use GeoGraphicsItems for rendering the grid
Allow for labels in GeoLineStringGraphicsItem.