Fix BinomialCoefficient problems from autotest (#3063)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23596 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Make sure Groebner package is loaded when we call mymainvar (#3063)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23597 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e