Chronicle of major events, and livelog

Log game events, such as entering a new dungeon level, breaking
a conduct, or killing a unique monster, in a new "Major events"
chronicle. The entries record the turn when the event happened.
The log can be viewed with #chronicle -command, and the entries
also show up in the end-of-game dump, if that is available.

This feature is on by default, but can be disabled by
defining NO_CHRONICLE compile-time option.

This also contains "live logging", writing the events as they
happen into a single livelog-file. This is mostly useful for
public servers. The livelog is off by default, and must be
compiled in with LIVELOG, and then turned on in sysconf.

Mostly this a version of livelogging from the Hardfought server,
with some changes.

src/polyself.c

@@ -646,7 +646,10 @@ polymon(int mntmp)
     }
 
     /* KMH, conduct */
-    u.uconduct.polyselfs++;
+    if (!u.uconduct.polyselfs++)
+        livelog_printf(LL_CONDUCT,
+                       "changed form for the first time, becoming %s",
+                       an(pmname(&mons[mntmp], flags.female ? FEMALE : MALE)));
 
     /* exercise used to be at the very end but only Wis was affected
        there since the polymorph was always in effect by then */