[test suite] env HOME tests, -R http resolve tests
[client] minor typo fix
[libfko] minor comment re-wording
[libfko] minor formating update for strtol_wrapper() range output messages
[test suite/client] memory leak bug fix and test coverage

This commit fixes a minor memory leak in the fwknop client before
calling exit() when an abnormally large number of command line arguments
are given.  The leak was found with valgrind together with the test
suite (specifically the 'show last args (4)' test):

==23748== 175 bytes in 50 blocks are definitely lost in loss record 1 of 1
==23748==    at 0x4C2C494: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==23748==    by 0x1112F1: run_last_args (fwknop.c:991)
==23748==    by 0x110D36: prev_exec (fwknop.c:916)
==23748==    by 0x10D953: main (fwknop.c:170)

Additional test coverage was added for the client via the
basic_operations.pl tests.
[server] Validate GPG sigs with libfko fko_gpg_signature_id_match() function
[test suite] --key-* arg validation with --fd 0