Design demo level (finish the demo.ini file)

[aaronamk]

Based on Nathan's concept

[rlatosky]

#173 Added barrel spawning

[rlatosky]

The "mast" branch adds functionality to add a mast at a specific position. We could either:

• Use the "Platform" declaration in the "demo.ini" file several times to match up with the height and width of the masts
• Use an equation to determine automatically how many platforms should be added to a mast
  (Don't know how to do the 2nd option, but I can try)