header should always contain links for all sections

When a section is entered, e.g. Admin the link in includes/header.jsp is
replaced with a normal string. Whilst a seemingly logical step this can make
navigation more difficult, not simpler. many pages end up in a dead end and if
you want to repeat the action, e.g. adding an interface by ip, then it is much
quicker to click on the normal admin link that you originally clicked on. I know
there is an equivalent link on the other side of the page, but this seems a
needless complication in the navigation. i would suggest that the jsp code is
removed in this point in header.jsp and a simple more static equivalent is left
there instead.