[giac] enabled tangent(function plot,point) if point not on curve and function is rational. Test: commented solve check for #equations=#unknowns.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28133 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@28134 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e