Early Access Episode 1 version 1.5.1

A small patch for PA (despite the size of the patch):

• Optimize sprites/textures/brightmaps using a better tool called oxipng.
  
• Remove unused sprites from Episode 1 (Early Access release only, not in demo).
  
• Add new slider graphics! No more cruddy looking sliders in the menus!
  
• Cutscene maps are now skippable with any key on the keyboard, or any button (aside Start/Back) on controllers.
  
• Some upstream patches that fixed custom resolution issues.
  
• Dropped support for the TI-84 Calculator and the Tandy 1000.