[giac] make limit(1/x^2,x,0) return +infinity instead of (unsigned) infinity

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31331 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Changing giac.js to the latest version in web/kickstart.xml

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31332 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e