Dataengine for browser bookmarks

[Jan Gerrit Marker]

Hello again,
sadly school turned in my way so I continued developing the bookmarks engine 
(http://quickgit.kde.org/?p=scratch%2Fjangmarker%2Fbrowserbookmarks.git&a=summary) 
today.

I moved the code for getting bookmarks into classes. These classes are 
compiled in their own libraries. It works but I'm not sure if I did it 
correctly.

Furthermore I added a default browser which currently falls back to the "kde" 
browser. Later it will get the correct browser from the default settings.

I would appreciate a look over the code to correct serious mistakes. If it is 
okay that way I'd like to move it into KDE Review.

Best regards,
Jan Marker (jangmarker)