Fixes Issue #197 - "Camera Range Display" verb now uses obj/machinery/camera/proc/can_see() to calculate which turfs are visible by cameras.
Each turf in camera-range is marked with a maptext number indicating how many cameras can see that turf.

IMPORTANT: Changed the default fonts of the skinfile. This works around an issue with byond, where certain font-faces can cause HUGE increases in memory usage client-side, giving the illusion of lag, or severe crashes.
Before changing the font-face to 'Arial': using the camera range display verb would cause dream-seeker's memory usage to climb from 146,000 K to 800,000 K (and greater, but that is the limit of my laptop's pagefile, hence crashing my entire system)
After changing the font-face to 'Arial': using the same verb (with same code) resulted in negligible memory usage increase in dreamseeker, and works absolutely fine.

Status displays and such were not affected by this bug as they use a different font to the default set in the skinfile.
It did however affect stuff such as mining satchels, and may explain why some users found the game extremely 'laggy' or crashy
Merge pull request #199 from Carn/Issue197

IMPORTANT: Fixes Issue #197 - "Camera Range Display" verb now uses obj/machinery/ca...