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/dothrow.c

@@ -1880,7 +1880,8 @@ thitmonst(
 
             /* attack hits mon */
             if (hmode == HMON_APPLIED)
-                u.uconduct.weaphit++;
+                if (!u.uconduct.weaphit++)
+                    livelog_printf(LL_CONDUCT, "hit with a wielded weapon for the first time");
             if (hmon(mon, obj, hmode, dieroll)) { /* mon still alive */
                 if (mon->wormno)
                     cutworm(mon, g.bhitpos.x, g.bhitpos.y, chopper);