Implemented ContourPlot, ticket #1995

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24557 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] Another attempt to make solveODE and Sample.3 connect to giac.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24558 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] fix typo

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24559 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Make sure view is not null in Touch

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24560 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e