Fix for #4255, should not cause #3636 again.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33433 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[cas] fix for Sum[2+3(n-1),n,1,n]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33434 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Fix for #4255: redundant CSS removed

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33435 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
update Giac tests

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33436 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e