[giac] fast, exact Ellipse.3 and Hyperbola.3

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26547 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
4.9.170.0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26548 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e