Goolge Drive client side saving and loading. TODO: i18n and test

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23843 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
fast derivatives working for eg (x < x1) * (a1 x² + b1 x + c1)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23847 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e