Polygons: move area & centroid calculations to the algos (part 3)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33224 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Polygons: move area & centroid calculations to the algos (part 4) eg IntersectRegion[Polygon[(1,1),(0,1),(1,0)],Polygon[(1,1),(0,1),(1,0)]]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33225 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
remove debugging

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33226 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e