Campaign select and Deathdealer

All current missions are now visible in campaign selection, even if you can't play them yet
Missions you haven't unlocked yet by completing the previous mission are now greyed out
Changed 'Work in progress' to 'More to come' in campaign select since I do plan on adding at least 3 more missions
Added the Deathdealer to the game (new weapon)
Added the Tarkar heavy ship