wrap known_hosts add and check methods
document Net::SSH2::KnownHost class
document known_hosts method
rename hostkey method as hostkey_hash and warn when the formed is used
wrap libssh2_session_hostkey
rename method knownhosts to known_hosts
readfile returns the number of entries read on success
fix syntax error, add missing semicolon
add new set of constants required by the new known_hosts feature
regenerate const-c.inc using libssh2 1.4.3 headers