Addition of automatic record ID retrieval; support for multiple YAML configurations

I have several domains with CloudFlare, and I love your utility.  I've been working on some improvements here and there and wanted to share them.

The first major improvement is automatic retrieval of the CloudFlare record ID.  This helps lower the bar for less experienced users.

The second improvement is support for multiple YAML confguration files.  The config.yaml will be grabbed by default, but the user can also pass the yaml file as the first argument to the program.  This allows the user to have multiple YAML files if they have multiple domains.