[giac] improved Solve.1 and Solutions.1

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25956 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] updated tests

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25957 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e