#4687 call Giac directly to fix  Integral[abs(sin(x)), 0, 2pi] in Input Bar

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37148 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[cas] support TrigCombine[(tan(x) + tan(2x)) / (1 - tan(x) tan(2x))]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37149 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e