Modifies login page to only display the user login when
first entering the web page. Before that the user login disappears
and it will displaye the barcode reader inputs as usual.
Makes use of the new header user-email, so this change is
related to that change in S2Mapper
Fixes CSS class to be dashed-case
Modifies css class queries in code. Modifies behaviour in
case of accessing directly to a tab page without user login first
Merge pull request #390 from emrojo/login-page

Add login page