Added "remember me"-checkbox

A checkbox for extending the session timeout to 10 days has been added
to the login page.
Fixed remember me option for LDAP
The remember me option now  works with LDAP login.
Fixed positioning of options menu

The options now gets the correct position even if
the user has scrolled down the page.
Moved login error text to new line
Merge pull request #60 from fredrikpersson/rememberme

Added "remember me"-checkbox
Merge pull request #69 from fredrikpersson/menupositionfix

Fixed positioning of options menu