Also works in the back/forward dropdown menus and in the go menu.
Either opens a new tab or a new window. NewTabInFront and the Shift
button determine wheter the new tab is in front.
Tabs openend by back/forward and up respect openAfterCurrentTab, Home not.
The history is copied for back and forward.
(And Ctrl+Left support.)

svn path=/trunk/kdebase/konqueror/; revision=379899