[giac] map surd to pow if possible, in order to improve simplifications. Improve normal(sqrt(2-sqrt(3)/4))

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25475 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
improved precision for intersect line/conic & conic/conic

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25476 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] fix extra )

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25478 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Fixed the issue with invalid number of parameters when trying to redefine the element.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25479 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e