Preparation for a Demo

Here is the changelog:

1567737721

• Created DemoManager
  
• Stage pipe teleports will no longer occur if set to a stage destination of 0
  
• Stage pipe teleport game objects are now set as enabled in the dev stage
  
• Game objects modified by demo mode now are automatically added to a list
  
• Readded name branding to title screen
  
• Demo tiles added to block stage pipe teleports when running in demo mode
  
• Stage pipe teleports will become disabled if running in demo mode
  
• Steam achievements will not unlock while running in demo mode
  
• Demo branding message appears on title screen if running in demo mode