Implemented colour coding in initiative list

Added a feature that means the colour of the combatant's name in the
list indicates their hp. Orange means <= half, red means <= a quarter
(need to do this for the wound, delay and dying lists too). Also added
effects group to bottom right although it is unpopulated at this point.
Tweaked colour coding

Dead combatants appear as grey now. If a wound drops a combatant below
zero, user is prompted to move that combatant to the dead and dying
list. Also tweaked highlight colour to proper light colour.