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/engrave.c

@@ -1072,7 +1072,8 @@ doengrave(void)
 
     /* A single `x' is the traditional signature of an illiterate person */
     if (len != 1 || (!index(ebuf, 'x') && !index(ebuf, 'X')))
-        u.uconduct.literate++;
+        if (!u.uconduct.literate++)
+            livelog_printf(LL_CONDUCT, "became literate by engraving \"%s\"", ebuf);
 
     /* Mix up engraving if surface or state of mind is unsound.
        Note: this won't add or remove any spaces. */