Support pathname in host when http(s) is specified

[AfzalivE]

If I do this currently:

api-diff \
--old.host https://api.mywebsite.com/api/v1/ \
--new.host https://api.mywebsite.com/api/v2/ \
--endpoint /myendpoint \
--method POST \
--input_params input_params.txt \
--output_mode html > output.html

Everything after .com gets stripped, which means it's not possible to test different versions of API on the same host.

This seems to only happen when I put "http" or "https" in the host urls.