[Utopia] Bombard them all, God will recognize His own

An overhaul of the orbital bombardment to make it more destructive but also more consitent. The Armageddon stance (added in Utopia) now has major and definitive impact on the targetted planet. ---------- Comptability : Anything that does not touch the file "events/orbital_bombardment.txt" Achievement friendly : No ---------- I always found that the orbital bombardment was an underdevelopped gameplay mechanic with very limited impact on planets. YOU DROP BOMB FROM SPACE, god damn it. Perhaps a official overhaul will eventually come in the next extension but in the meantime I have decided to complete rewrite it. With each passing month as the planet is bombarded, one of these effect apply (depending on the chosen stance) : SOFT STANCE - 5% chance of killing a population (sentient or not). If a population is killed, there is 25% chance of the tile is destroyed and a tile blocker is apply. Otherwise, the tile's building is ruined (if applicable). - 5% chance of destroying a non-populated tile and apply a tile blocker. - 10% chance of ruining a building. The last sentient pop cannot be killed. LIMITED STANCE - 10% chance of killing a population (sentient or not). If a population is killed, there is 50% chance of the tile is destroyed and a tile blocker is apply. Otherwise, the tile's building is ruined (if applicable). - 10% chance of destroying a non-populated tile and apply a tile blocker. - 20% chance of ruining a building. The last sentient pop cannot be killed. FULL STANCE - 20% chance of killing a population (sentient or not). If a population is killed, there is 80% chance of the tile is destroyed and a tile blocker is apply. Otherwise, the tile's building is ruined (if applicable). - 40% chance of destroying a non-populated tile and apply a tile blocker. - 60% chance of ruining a building. The last sentient pop cannot be killed. ARMEGEDDON STANCE (here come the serious business) - 50% chance of killing a population (sentient or not) and the tile is destroyed with