Set correct orientation for convex polygons

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31970 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Move algoVertex to GeoPolygon3D (no need in 2D)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31971 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e