[Project_owners] Hide statusbar icon

[Neil]

Michael Vincent van Rantwijk, MultiZilla wrote:

> You can use: "browser.toolbars.showbutton.mybuttonid" for which 
> SeaMonkey has a pref observer setup, which works for me (when I use a 
> button ID like: mybuttonid-tbbutton).

These prefs will be disabled in SeaMonkey 2.0, once we get customisable 
toolbars working.