Internet Explorer 8 is not supported in Web, because it has no Canvas

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@32716 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Fix for #4200

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@32717 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Clean code

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@32718 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e