[giac] should improve desolve(y'=y*(2-y)) (ticket 3416).
Should also eliminate non used variable in arg2 of gbasis.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26253 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@26254 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e