change "Cancel" to "Close" in customize toolbar dialog

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23880 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
fast derivatives: add check to make sure Integral(polynomial) not called

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23881 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Ticket #3065: nothing interesting now, but progressing step by step (to evaluate what is good and what is wrong in my patch)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23882 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e