Merge pull request #94 from zijistark/dev

Random Rulers
Added icon for Random Rulers
Merge pull request #95 from thefinestsieve/beta

Added icon for Random Rulers
Added new Immortal trait icon
Merge pull request #96 from thefinestsieve/beta

Added new Immortal trait icon
even_if_dead is apparently deprecated

See:
http://forum.paradoxplaza.com/forum/showthread.php?746159&p=16742373#post16742373
PB+SWMH compatibility
Muslim and tribal invasion border reqs, consistency
Overhauled welcome event text for clarity and to be up-to-date
Halved BATTLE_WARSCORE_MULT for invasion CB [+tribal+viking]