Added support for Cloudflare and multi domain support for namecheap

As featured at: https://support.cloudflare.com/hc/en-us/articles/200168816-Does-CloudFlare-work-with-Dynamic-DNS-Can-I-update-my-DNS-records-remotely-

Namecheap improvements: https://robertianhawdon.me.uk/2010/09/03/making-ddclient-work-with-multiple-domains-on-namecheap/
When I run this version on the default sample config, I get an error:

```bash
$ /usr/local/opt/ddclient/sbin/ddclient
Bareword found where operator expected at /usr/local/opt/ddclient/sbin/ddclient line 3964, near "s/\.$config{$key}{zone}$//r"
syntax error at /usr/local/opt/ddclient/sbin/ddclient line 3964, near "s/\.$config{$key}{zone}$//r"
Execution of /usr/local/opt/ddclient/sbin/ddclient aborted due to compilation errors.
```