--testShaders as argument for testing shaders in desktop

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37042 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
fix for spline (not using inhomogeneous coords)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37043 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e