Issue/386 encoding fixes

[blepabyte]

Proposed Changes

• Fix return type in docstring of Requester.request
• Fixes File.download hangs in debug statement indefinately #386 by avoiding call to response.text (response.json() internally calls response.text) - the underlying issue is that the requests library relies on chardet to determine the encoding of data, but it's impractically slow for binary data (which can occur when File.download is called on a non-text file) so effectively hangs
• Adds an option to return bytes from File.get_contents directly

Fixes #386 .

Note: I added a test test_request_get_binary but couldn't find a way to make it work with theregister_uris function in util by adding a fixture since JSON doesn't seem to support binary data.

[coveralls]

Coverage remained the same at 100.0% when pulling 52db66f on blepabyte:issue/386-encoding-fixes into e74ca80 on ucfopen:develop.

[Thetwam]

Great find and solution. Thanks for the help @blepabyte !

Travis is being super slow, but it passed in py 3.6 there and on 3.8 on my local. Am going to override merge.