Also compute hashes with Windows newlines

Currently, [the list of known-good policies](https://github.com/EFForg/dnt-policy/blob/master/dnt-policies.json) is computed using literal sha1 hashes of the files in the repo. If people save and copy the files with certain tools on Windows, they may wind up with [different newlines](https://en.wikipedia.org/wiki/Newline#Representations). We should probably at least handle the CR+LF case correctly.

Start by locating the code that computes the hashes and the use of dnt-policies.json as the known-good list. Trace how file newlines are read, then verify that policy files using LF and CRLF produce accepted hashes. The payload does not name a test, so add or run the repository's relevant hash checks if available.

Written by the indexing model from the issue text.