Menu and UI update (part 1)

I finally started working on the last big visual thing I'd postponed for so long : making the menus a bit handier and prettier.

-Changed the text font -New menu UI design, including new button and icon designs -You can now navigate menus with arrow keys and confirm with pickup key (space by default). This isn't implemented on all menus yet -When completing a level, you now go back to the worldmap and an unlock level animation is played, if relevant -Fixed timed ticking while the level is paused -Level design tweaks

I still have some work ahead of me for the menus I want to have, so I'll keep working on these aspects of the project.