SC2Mapster

Added 4 expansions at the top and bottom of the map: 2 islands and 2 accessible by ramp.
Added LOS blockers to the mains to prevent blinking directly into them.

Still not sure about the large open spaces above and below the craters, but I'm hesitant to add something just to take up space, as that could easily end up being cluttered and annoying. I may adjust the terrain there at some point.