Merge branch 'master' of git://github.com/gwaldron/osgearth

Conflicts:
	src/osgEarthQt/MultiViewerWidget
	src/osgEarthQt/MultiViewerWidget.cpp
	tests/feature_geom.earth
Added option to set touch sensitivity
Typo in last commit
Type
Add to last commit
Fix Gdal driver to use fast subsampling to create elevation layers.
FIX compilation problem on Windows. Change 'round' to 'osg::round'
BuildGeometryFilter: fix copy/paste bug that prevents single-point Point geometries from being built
RangeUniformCullCallback: add debugging code
VirtualProgram: add accept callback to compare set
OgrUtils: formatting
DepthOffset: try a vertex-shader-only method that is compatible with the logarithmic depth buffer
MeshSubdivider: stripify subdivided line geometry to support correct stippling.
StringUtils: parse hex integers, so you can use hex values in the earth file (e.g. for stipple patterns)
Add doc for LogDepthBuf
Update utilities.rst
LogarithmicDepthBuffer: fix for rtt cameras
ExampleResources: revert mistaken change
RenderSymbol: add clip plane support
Add clip plane support