The gandi api has changed its url for a more stable
one. Although https://dns.beta.gandi.net will continue to
work for the foreseable future, this commits updates the
url to new official one.
dns_dyn.sh, remove empty line at end
dns_dyn.sh, remove trailing spaces at end of line
Replace 'head -n' with the '_head_n' function
Update main README.md DNS API list