NPE fix

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26483 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] improvements to Geometry commands

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26484 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e