Context menu - "Select another" menuitem improvements: alignment, position of this menuitem.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24785 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[giac] use <= and >= rather than Unicode ≤ ≥

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24786 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
[web] make sure {} is displayed in CAS View

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@24787 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e