Fixed IPv6 variable name mismatch. Note: IPv6 flags on Windows require Python >=3.4
Added tlds.txt file from http://data.iana.org/TLD/tlds-alpha-by-domain.txt
Lower case all TLDs
Don't treat comments in tlds.txt file as TLDs.
Removed unnecessary dependency
Indent error messages for failed MX resolution properly
Ensure user entered hostname isn't presented as a typo too
Initial commit of Google Safe Browsing integration. Still needs integrating with the www/webmail/m subdomains.
Merge pull request #3 from neonbunny/master

Bug fixes and initial Google Safe Browsing integration from @neonbunny - awesome and thanks again!