[cas] distingiush between 2d and 3d points properly (fix for eg Dot[(-5+k,-5+k), (3,9)] )

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37704 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
5.0.36.0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37705 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e