Ticket #3407: Web spreadsheet rendering - taking into account colored cells which are not filled (even if it makes things a bit slower)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26172 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
* polygons : use only 2D points (even after copy internal)
* refactor apply matrix
* fix bad 3D drawing for GeoSegment

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26173 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] fix integral of cos(x)*ln(1+cos(x)), changed error message in Groebner basis computation when number of variables is too large.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26174 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e