Doc: Added some documentation

...to ioutputpane, inavigationwidgetfactory, ioptionspage and
removed now redundant comments

Authors:
    Falko Arps <fjarps@aol.com>
    Sven Klein <klein.sven@gmx.de>
    Giuliano Schneider <gs93@gmx.net>

Change-Id: I49651dfd4304a2e9a0ba2262a16f812d1fca773e
Reviewed-by: Eike Ziller <eike.ziller@digia.com>