Remove SSL Certificates

• Option to remove/delete SSL Certificates [#59]

Add support for FTP and PasswdStrength modules

Adds support for Cpanel's FTP [#55] and PasswdStrength [#51] modules.
Also drops support for 1.8's YAML engine: Syck, and updates the codebase to use 1.9 style hashes [#54]

Pass same options to Cpanel::Ssl and Whm::Cert

Pass (almost) same options when creating certificate signing requests [#50]

New feature and another updates

• Update faraday and faraday_middleware gems [#47]
• List available Cpanel themes [#46]
• Add license to gemspec [#45]
• Raise for invalid nor unresolvable domains [#43]