Auto-scroll and login/register button fixes

The auto-scroll code was a bit buggy. It would not scroll for embedded images if they were of a certain height or more and it would not scroll in any case for embedded videos. Additionally, the scrolling was dependant on an additional jQuery plugin which is unnecessary. Therefore I have removed dependency on that plugin and replaced it with standard jQuery.

The login/register buttons would show originally for a second or so when the page loaded as it was checking if a database was available or not. This lead to confusion, at least for me. I therefore reversed the situation so that the buttons are hidden by default. Additionally, the buttons do not re-show (re-hide previously) when clicking on "Home" from either of the 4 options (Connection, Settings, Register, Login). I have fixed this the only way I could figure out how, potential improvements to be made there.