Allow Center with circle, Angle with polygon

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26890 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Redefine dialog fixes: title, error handling

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26891 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
new button (cancel) added

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26893 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Redefine, customkeys

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26895 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e