Re-added sanity check before calling safebrowsing, with additional comment to explain rationale.
Added range check for TCP port numbers and made use of argparse's "default" feature.
Reverted Google SafeBrowsing client string to "api" as per API docs.
Realigning with origin master branch
re-added a couple of changes I missed out of conflict resolving
Fixed a couple of things spotted by PyCharm's static analysis
Merge pull request #9 from neonbunny/master

Port number range checking