Fix player being invisible upon loading into game again

When I did #567, I didn't test it. And I should have tested it, because
it made the player invisible. This is because map.resetplayer() also
sets the invis attribute of the player to true as well, and I only undid
it setting game.lifeseq to 10.

So instead, I'll just add a flag to map.resetplayer() that by default
doesn't set game.lifeseq or the player's invis attribute. And I tested
it this time, and it works fine. I tested both respawning after death
and exiting to the menu and loading in the game again.

desktop_version/src/Map.h

@@ -69,6 +69,7 @@ public:
 
     void showship();
 
+    void resetplayer(const bool player_died);
     void resetplayer();
 
     void warpto(int rx, int ry , int t, int tx, int ty);