Checkboxes for view menu (#3352) - works but there is one thing to fix yet: there is too big distance between the checkboxes and the texts of menuitems.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@25793 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e