New master lfun query_userlist().

Introduces a new master function for querying the
userlist (i.e. data from  the secure savefiles).
Contrary to get_userinfo() it returns specific
records from the userlist instead of a whole array.

The existing get_userinfo() function had a very
ill-defined interface. It returned an array which
was usually accessed by the *internal* symbolic
constants from userinfo.h plus an offset. These
could therefore never be changed internally. It
was also completely undocumented.

Also removes the now obsolete query_player_object()
which was also undocumented and used at only two
places (one being the master itself).

Change-Id: I5948deb69fd750dadd746f9089ba9ee9170c8a81
diff --git a/secure/master.h b/secure/master.h
index 14c9fab..958043c 100644
--- a/secure/master.h
+++ b/secure/master.h
@@ -99,7 +99,7 @@
 protected mixed *get_full_userinfo(string user);
 public mixed    *get_userinfo(string user);
 public int       get_wiz_level(string user);
-public string    query_player_object( string name );
+public mixed     query_userlist(string user, int prop);
 public int       query_wiz_level(mixed player);
 int              update_wiz_level(string user,int lev);
 protected void   set_guilds(string player, string *guilds);