SSL error even if cert / verify is set #93
Description
Since prance does not support passing cert / verify parameters the request to fetch the spec will fail if the source is a url that requires a certificate / SSL.
This issue can be worked around by downloading the spec first, which can be done by a custom keyword (python or RequestLibrary) that uses the cert / verify information.
To make this easier for the user, a retry mechanism can be added that attempts to download the spec file using the cert / verify information in case an SSL error occurs. If this succeeds, the file can be saved to the RF outout dir and the library can parse the spec from that location.