Session clock!

This update adds a session clock which shows you exactly how long you've been playing Beat Saber since launching the game, and also how much of that time you've spent actually playing songs.
You can change the position of the new session clock in the Tweaks.cfg file

Thanks to Shoko84 for adding this cool tweak!

Other notes:

• The settings are now split into two submenus: Interface Tweaks [1] and Interface Tweaks [2]
• Changed score mover default position / size
• Reduced log spam