Tweaked WIN32 conditional for using inet_ntoa instead of inet_ntop to apply only to versions below Vista (WINVER <= 0x0600)

(Shawn Wilson) This adds better source IP logging for fwknopd log messages.
Closes #70.

[test suite] minor update to not count HMAC OpenSSL tests against non-ascii HMAC keys when the hexkey option is not supported

Pull in forked upstream

Bug fix to ensure to release memory when invalid access stanza dates are set
and fwknopd has to exit.  This leak was caught with the test suite in
--enable-valgrind mode based on the following output:

==31947== 568 bytes in 1 blocks are still reachable in loss record 1 of 1
==31947==    at 0x4C2CD7B: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==31947==    by 0x52EE42A: __fopen_internal (iofopen.c:73)
==31947==    by 0x1116A2: parse_access_file (access.c:909)
==31947==    by 0x10BAD5: main (fwknopd.c:194)

This allows to update dump_transmit_options() to use the log module to dump data.

perror() is also replaced by log_msg()

This merges changes from Franck Joncourt for issues #55 (log module for fwknop)
and #64 (hostname resolution not working for -P icmp spoofing).

This commit helps to ensure correctness of strlcat() calls in support of fixing
issue #2.

mrash/fwknop#64

This commit helps to ensure correctness of strlcpy() calls in support of fixing
issue #2.