I found that it is possible to programaticaly put login/logout buttons in header (in Silverstripe CMS) with this code.
<% if CurrentMember %>
<a href="/Security/login">Log in</a>
<% else %>
<a href="/Security/logout">Log out</a>
<% end_if %>
If I put "/Security/login" and "/Security/logout" in page name then it works, But if I put it in page template Page.ss then I cant see it (after sitename/dev/build and sitename/?flish=all)
Can someone help with Silverstripe 3.1 and "simple" template