Write a bunch of module documentation.

This commit adds or improves the module-level documenation for:

  buffers.c circuitstats.c command.c connection_edge.c control.c
  cpuworker.c crypto_curve25519.c crypto_curve25519.h
  crypto_ed25519.c crypto_format.c dircollate.c dirserv.c dns.c
  dns_structs.h fp_pair.c geoip.c hibernate.c keypin.c ntmain.c
  onion.c onion_fast.c onion_ntor.c onion_tap.c periodic.c
  protover.c protover.h reasons.c rephist.c replaycache.c
  routerlist.c routerparse.c routerset.c statefile.c status.c
  tor_main.c workqueue.c

In particular, I've tried to explain (for each documented module)
what each module does, what's in it, what the big idea is, why it
belongs in Tor, and who calls it.  In a few cases, I've added TODO
notes about refactoring opportunities.

I've also renamed an argument, and fixed a few DOCDOC comments.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/or/dns_structs.h b/src/or/dns_structs.h
index bb67459d7b..bc6067213d 100644
--- a/src/or/dns_structs.h
+++ b/src/or/dns_structs.h
@@ -1,3 +1,15 @@
+/* Copyright (c) 2003-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2016, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file dns_structs.h
+ *
+ * \brief Structures used in dns.c. Exposed to dns.c, and to the unit tests
+ * that declare DNS_PRIVATE.
+ */
+
 #ifndef TOR_DNS_STRUCTS_H
 #define TOR_DNS_STRUCTS_H