Closes ticket 4572.

Bugfix on 0.2.2.1-alpha, which added the orginal HTTP proxy
authentication code.  Fix for bug 5593.

This is just refactoring work here. The old logic was kind of
convoluted, especially after the bug 5572 fix. We don't actually need to
distinguish so many cases here. Dropping detection of the
"!old_options || !old_options->DynamicDHGroups" case is fine because
that's the same that we'd do for clients.

Also add a changes file for bug 5572.

As per ticket 5569

tor_vsscanf() is supposed to return the current number of matches on
match failure.

The message only means that we're publishing a new descriptor when we
are actually in some kind of server mode, and publication is on.

Fix for bug 3942; bugfix on 0.2.3.2-alpha.

Conflicts:
	src/or/config.c

it's fine with me if we change the current convention, but we should
actually decide to change it if we want to.

It is for the not-yet-implemented bridge community design.

Conflicts:
	src/or/config.c

Conflict was in or_options_free, where two newly added fields had free
calls in the same place.

This fixes a side-channel attack on the (fortunately unused!)
BridgePassword option for bridge authorities.  Fix for bug 5543;
bugfix on 0.2.0.14-alpha.

One of our unit tests checks that they behave correctly (giving an
error) when the base is negative.  But there isn't a guarantee that
strtol and friends actually handle negative bases correctly.

Found by Coverity Scan; fix for CID 504.

Coverity doesn't like the fact that we were storing the value of
parse_config_line_from_str() but not checking it in a couple of
cases.

Fixes CID 505 and 506.

Found by Coverity Scan; fix for CID 507; bugfix on 0.2.3.13-alpha.

Calling crypto_cipher_free(NULL) is always safe, since (by
convention) all of our xyz_free() functions treat xyz_free(NULL) as
a no-op.

Flagged by coverity scan; fixes CID 508 and 509.

A previous commit in the 5527 branch had moved
router_get_mutable_by_digest(digest_rcvd) to happen before we did
tor_assert(digest_rcvd), which would have defeated the purpose of
the assert.

Specifically, I believe it dates back to when extend cells had address:port
but no digest in them. The special edge case is certainly not worth the
complexity these days.

Look up the router using the digest instead of looping over all routers.

last_guessed_ip becomes a tor_addr_t.

Most parts of router_new_address_suggestion() learns
about IPv6 (resolve_my_address() is still IPv4 only).