(part I.) Issue 6995: Display an icon for read only properties
Merge branch 'jsd2' of github.com:firebug/firebug into issue6995
(part II. infotip) Issue 6995: Display an icon for read only properties
Merge branch 'jsd2' of github.com:firebug/firebug into issue6995
(part III., feedback incorporated) Issue 6995: Display an icon for read only properties
Merge branch 'issue6995', remote-tracking branch 'origin' into jsd2