Reset LastValidPlayerPos when starting a new game

This fixes the player spawn position when starting a new game after
already having loaded an existing game. The bugged spawn position
was visible for a few frames before the intro cutscene started and
could activate triggers causing system messages to be displayed before
they should be.

Fixes: bug #140

src/game/Player.cpp

@@ -2660,12 +2660,15 @@ void ARX_PLAYER_Invulnerability(long flag) {
 }
 
 extern Entity * FlyingOverIO;
+extern Vec3f LastValidPlayerPos;
 
 void ARX_GAME_Reset(long type) {
 	arx_assert(entities.player());
 
 	DeadTime = 0;
 
+	LastValidPlayerPos = Vec3f_ZERO;
+
 	entities.player()->speed_modif = 0;
 
 	LAST_JUMP_ENDTIME = 0;