Throw error on 0th degree polynomials, fixes #1391

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24932 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Improving last commit [see #1394]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24936 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e