minor README update
[test suite] better loop output for fko-wrapper
[test suite] minor display_ctx() call position update
[libfko] ensure a NULL HMAC key is properly handled
bumped version to 2.6.0
(Marek Wrzosek) Update docs to reflect random 'digits' use instead of 'bytes'

Suggested doc update to fwknop man pages to accurately describe the usage
of digits instead of bytes for SPA random data.  About 53 bits of entropy
are actually used, although this is in addition to the 64-bit random salt
in for key derivation used by PBKDF1 in Rjindael CBC mode.