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/write.c

@@ -231,7 +231,9 @@ dowrite(struct obj *pen)
     }
 
     /* KMH, conduct */
-    u.uconduct.literate++;
+    if (!u.uconduct.literate++)
+        livelog_printf(LL_CONDUCT,
+                       "became literate by writing %s", an(typeword));
 
     new_obj = mksobj(i, FALSE, FALSE);
     new_obj->bknown = (paper->bknown && pen->bknown);