[giac] Fix for sign 

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25150 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] should return 3 for solve(2^x=8)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25151 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@25152 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e