Add certificate for auth and RPC calls.

[panvid]

For my usage I want to log all HTTP calls. This is only possible with a SSL-man-in-the-middle tool (like CharlesProxy).

For this reason I need to log all calls with my own SSL cert to:

• sso.pokemon.com
• pgorelease.nianticlabs.com

This commit allows to add a cert attribute to config.json:

{
   "cert": "PathToCert"
}

For more infos: StackOverflow - check Python requests with charles proxy for HTTPS.

[globeriz]

Does this ignore untrusted CA errors?

[panvid]

@globeriz Not yet I think.

[panvid]

@globeriz What will be happen with this PR?