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/spell.c

@@ -492,7 +492,10 @@ study_book(register struct obj* spellbook)
 
             if (read_tribute("books", tribtitle, 0, (char *) 0, 0,
                              spellbook->o_id)) {
-                u.uconduct.literate++;
+                if (!u.uconduct.literate++)
+                    livelog_printf(LL_CONDUCT,
+                                   "became literate by reading %s", tribtitle);
+
                 check_unpaid(spellbook);
                 makeknown(booktype);
                 if (!u.uevent.read_tribute) {