Implement a new event to receive notifications when a player score has changed.

Fix syntax error in enumeration declaration.
Fix compilation error on const correctness in player method for changing player world.

source/SqBase.hpp

@@ -384,6 +384,7 @@ enum EventType
     EVT_PLAYERSCORE,
     EVT_PLAYERWANTEDLEVEL,
     EVT_PLAYERIMMUNITY,
+    EVT_PLAYERALPHA,
     EVT_VEHICLECOLOUR,
     EVT_VEHICLEHEALTH,
     EVT_VEHICLEPOSITION,