Added supermatter console icon set

Added custom icons for the supermatter computer to the file at
icons\obj\computer.dmi which includes supermatter, supermatter_alert:0,
supermatter_alert:1, supermatter_alert:2 (which is animated blinking
red), supermatterb, and supermatter0.

I followed other computer console standards as far as I saw on the dmi
file.  Make an issue if the icons are missing something, thanks!