Merge branch 'terencehill/hud_updates' into 'master'

Merge branch 'terencehill/hud_updates' into 'master'

HUD updates

* Display more panels (engineinfo, modicons and timer) while showing the scoreboard (changes implementation of how panels fades when showing the scoreboard)
* Vote panel: display the bg too while the menu is shown
* When the game ends timer shows elapsed time
* Apply global hud alpha to the map vote panel, fixing fading when showing the scoreboard
* Mark panels that can't be disabled manually (main panel cvar doesn't exist) so hud editor considers them enabled

See merge request !353