Bug Fixes & Misc. Improvements

• Upgraded to the latest stable version of Unreal Engine (4.7)
  
• Improved performance in the starting area, saving ~3ms per frame (the difference between 50 & 60 fps)
  
• The correct footstep sounds should now always play based on the surface the player is walking on
  
• Overhauled the saving & loading system. Saved games are no longer overwritten; each time the game is saved, a new save file is created
  
• Collision issues may be resolved. No falling through the world while testing, but that doesn't necessarily mean it's fixed
  

Known Issues
There's a rare bug (that also occurred in older versions) causing a saved game to become corrupt. We haven't been able to fix this issue but the changes to the save system means that if this bug does corrupt a save file, it can be deleted and you'll only lose one checkpoint worth of progress at most, rather than your entire game. We're still working to get this resolved but so far, we haven't been able to reproduce the bug - making it hard to track down exactly what is going wrong.