HappyResponse returns true if we want to continue scraping this thing.

Hash returns a SHA1 hash of the host and path.

IsNiceFileType returns true if the file extension is of type html (or unknown).

ParseURL is a helper function that takes a string url, trims whitespace, parses into a url.URL and finally checks whether it fits our url requirements.

ScrapeDaTing gives us a yes/no on whether or not we should scrape the following URL, based on our opinionated filters.